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Bowen, John George. "C-H activation in the formation of C-N and C-O Bonds." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685335.
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The regioselective activation of C-H bonds and subsequent transformation into desirable functional groupS is an attractive prospect in organic synthesis. We have developed two novel C-H functionalisation reactions; the first is an intramolecular, sulfonamide directed, C-H amination reaction for the synthesis of 3_phenylisoindolinone derivates and the second is a sulfonamide directed ortho C-H acetoxylation reaction. Both isoindolinones and phenol derivatives of sulfonamides are important motifs in numerous pharmaceutically relevant compounds. The Cull-catalysed intramolecular C-H amination reaction for the synthesis of substituted 3-phenylisolindolinone derivatives (Scheme i) was found to be tolerant to substitution on both aromatic rings, however, no reaction was observed on exchanging the tethered aryl group for an alkyl group. Mechanistic investigations revealed that C-H cleavage was not part of the rate-determining step which is likely to be coordination of the copper catalyst to the sulfonyl amide. Substitution of the tethered phenyl ring (R2 ) and a subsequent Hammett analysis indicated that this coordination may be accelerated by a cation-IT interaction between CU11 and the pie system of the aryl group.
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Persson, Andreas K. Å. "Palladium(II)-Catalyzed Oxidative Cyclization Strategies : Selective Formation of New C-C and C-N Bonds." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-75435.
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The main focus of this thesis has been directed towards preparation and oxidative carbocyclization of en-, dien- and aza-enallenes. In the first part of this thesis, a stereoselective oxidative carbocyclization of dienallenes was realized. By employing cheap and readily available palladium trifluoroacetate we were able to efficiently cyclize a variety of dienallenes into hydroxylated carbocycles in high yield and high selectivity. This oxidative process was compatible with two different reoxidation protocols: one relying on p-benzoquinone (BQ) as the oxidant and the other employing molecular oxygen as the oxidant. In the second part of the thesis the carbocyclization methodology was extended to include carbocyclization of aza-enallenes. This was achieved in two distinct steps. First, a copper-catalyzed coupling of allylic sulfonamides with bromoallenes was developed, giving access to the corresponding aza-enallenes. Subjecting these substrates to catalytic amounts of palladium acetate, along with BQ as the oxidant, rendered N-heterocycles in good yield. The reactivity of these N-heterocycles towards activated dienophiles was later exploited in a tandem (aerobic) oxidative carbocyclization/Diels-Alder reaction. The third topic involves efficient oxidative arylative/borylative carbocyclization of enallenes. These reactions, catalyzed by palladium acetate, relies on transmetallation of a (σ-alkyl)palladium(II) intermediate with diboranes or arylboronic acids. With this novel methodology we were able to obtain an array of arylated or borylated carbocycles, as single diastereomers, in high yield. Finally, we developed a palladium(II)-catalyzed cyclization of allylic carbamates. This mild, operationally simple, and scalable catalytic reaction opens up access to an array of oxazolidinones in high yield and excellent diastereoselectivity.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 6: Manuscript.
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Lishchynskyi, Anton. "Development of new methods for the asymmetric formation of C-N bonds." Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAF026.
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Au cours de ce travail de nouvelles méthodes pour la formation de liaison C-N ont été développées. Dans la première partie de cette thèse une application de catalyse métal-ligand bifonctionnelle pour la réaction énantiosélective aza-Michael est démontrée. Dans la deuxième partie nous présentons le travail sur les cyclisations, en utilisant des alcaloïdes du quinquina facilement disponibles, comme catalyseurs des plus prometteurs, fournissant des β-amino-acides d’indoline avec jusqu'à 98% ee. Parmi eux, l’hydroquinidine ressort du lot comme étant le catalyseur donnant le meilleur excès énatiomérique. La troisième partie est liée à l'élaboration d'un nouveau processus intermoléculaires de diamination de styrènes, diènes et triènes, utilisant des bis-sulfonylimides comme source d'azote, en combinaison avec le diacétate de iodosobenzène, qui fournit une approche intéressante et efficace de diamines vicinales biologiquement et chimiquement important. La réaction peut être effectuée à température ambiante sans avoir besoin de protection par atmosphère inerteThe concept of metal-ligand bifunctionality was successfully applied for an enantioselective aza-Michael reaction by employing well-defined ruthenium amido complexes. The catalyst was optimised and the corresponding chiral indoline β-amino acid derivatives were obtained with high enantioselectivities. Next, a straightforward enantioselective bifunctional organocatalytic approach was also developed. Employing hydroquinidine as catalyst the corresponding cyclic products were obtained in excellent enantioselectivities and quantitative yields. These compounds can be selectively deprotected and applied to peptide synthesis. Finally, we have developed unprecedented diamination reactions of styrenes, butadienes and hexatrienes employing easily accessible hypervalent iodine(III) reagents under robust reaction conditions. The first examples of the metal-free 1,2-diamination of butadienes were demonstrated and this oxidation methodology was further extended to the highly attractive 1,4 installation of two nitrogen atoms within a single step
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Mane, K. D. "Enantioselective synthesis of bioactive molecule and development of synthetic methodologies involving formation of C-C, C-N bonds." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2022. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/6140.
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Huang, Xiaohua 1973. "Palladium-catalyzed C-C, C-N and C-O bond formation." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/29639.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2003.Vita.
Includes bibliographical references.
New methods for Pd-catalyzed cross-coupling reactions of aryl halides or arenesulfonates are described. Key to the success of these transformations is the proper choice of ligand and reaction conditions. Palladium catalysts supported by bulky, monodentate phosphine ligands with a biaryl backbone or the bidentate ligand, Xantphos, effectively promote the formation of ca-aryl carbonyl compounds. Base-sensitive functional groups are better tolerated when a weak base, such as K3PO4, is used. One of the most difficult transformations in Pd catalysis, the intermolecular C-O bond formation between primary alcohols and electron-neutral or even electron-rich aryl halides, was effectively promoted by the use of a new generation of ligands, 3-methyl-2-di-t-butylphosphinobiaryl. The one-step synthesis of ligands from cheap starting materials, as well as the mild reaction conditions employed for the coupling reactions, enables the practical use of Pd catalysis to access aryl alkyl ethers for the first time. Continuing study of Pd-catalyzed C-N bond-forming processes using biaryl monophosphine ligands led to the discovery of a structural derivative of these ligands, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl. This ligand, in combination with a Pd source, produces a catalyst system with both a greater degree of activity and of stability than those that use our previous ligands. Substrates that were not amenable to Pd catalysis previously are reexamined using this new catalyst system, and excellent results are obtained.
by Xiaohua Huang.
Ph.D.
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Correia, Camille. "Oxidative C-C bond formation via metal-catalyzed coupling of two C-H bonds." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114441.
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This thesis describes the formation of new C-C bonds from the direct oxidative coupling of two C-H bonds, through the use of metal catalysts for activation. First, three different oxidative Cross-Dehydrogenative-Coupling (CDC) reactions will be presented. Initially, through the use of an organic co-catalyst, N-hydroxyphthalimide (NHPI), oxygen could be utilized as the terminal oxidant for the metal catalyzed alkylation of benzylic C-H bonds with 1,3-dicarbonyls and ketones in Chapter 2. The reaction was found to be feasible for a variety of substrates with readily enolizable C-H bonds. Next, the 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) mediated alkynylation of sp3 C-H bonds was studied. A novel copper (I) triflate catalyzed CDC reaction of unactivated benzylic C-H bonds and terminal aromatic alkynes is presented in Chapter 3. After further studies, the alkynylation of benzylic ethers could also be realized in the presence of a catalytic amount of silver (I) triflate, as described in Chapter 4. Both procedures were found to be amendable for aromatic terminal alkynes, however could not be extended to aliphatic alkynes. Finally, a palladium catalyzed Minisci-type reaction will be described in Chapter 6. Peroxide generated α-hydroxyalkyl radicals could be reacted with azines in moderate to good yields. A stoichiometric amount of acid, used in the traditional Minisci reaction, was replaced by a catalytic amount of palladium dichloride.Cette thèse décrit la formation de nouvelles liaisons C-C par activation oxydative directe de deux liaisons C-H grâce à l'utilisation de métaux de transition comme catalyseurs. La première partie présentera trois différentes réactions de Cross-Dehydrogenative-Coupling (CDC) oxydantes. Dans un premier temps, sera présentée dans le chapitre 2, la réaction d'alkylation de liens C-H benzylique par 1,3-dicarbonyles et cétones. Ce system a démontré son efficacité sur une large variété de substrats contenant des liaisons C-H enolysable. De plus il a été rendu possible, grâce à l'utilisation d'un co-catalyseur organique, le N-Hydroxyphthalimide (NHPI), d'utiliser l'oxygène moléculaire comme oxydant terminal. Dans un second temps, nous étudierons l'utilisation du 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) comme médiateur pour l'alkynylation de liaisons sp3 C-H. Une nouvelle CDC réaction catalysée par le triflate de cuivre (I) sera présentée dans le chapitre 3, entre un alcyne et une liaison C-H benzylique. Le chapitre 4 présentera le développement de cette réaction à l'alcynation d'éthers benzyliques en présence d'une quantité catalytique de triflate d'argent (I). Ces deux procédures sont seulement applicables pour les alcynes vrais aromatiques. Finalement, le chapitre 6 portera sur la réaction de Minisci catalysée par le palladium. Le peroxyde radical α-hydroxyalkyl généré lors de la réaction est capable de réagir avec les azines. La quantité stœchiométrique d'acide nécessaire lors de la traditionnelle réaction de Minisci, a été remplacée par une quantité catalytique de dichloro palladium.
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Laren, Martijn Wouter van. "Palladium-catalyzed C-H and C-N bond formation." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2004. http://dare.uva.nl/document/75422.
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Karabal, P. U. "Asymmetric synthesis of bioactive molecules and formation of C-N, C-Br and C-I bonds via olefin functionalization." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2014. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2219.
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Thakur, V. V. "Asymmetric synthesis of bioactive molecules and formation of C-C, C-N, C-Br, S-O bonds by transition metal catalysis." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2002. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2338.
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Midya, S. P. "Transition metal catalyzed (de) hydrogenative C-C and C-N bond formation." Thesis(Ph.D.), CSIR-National Chemical laboratory, Pune, 2018. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/4568.
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Lee, Alison Victoria. "Catalyst and methodology development for regioselective C-N and C-C bond formation." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/31377.
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The related investigations of catalytic hydroamination as a key step in synthetic methodology development and the synthesis of new hydroamination catalysts are reported in this thesis. The first section focuses on methodology development for the application of a bis(amidate)bis(amido) titanium hydroamination precatalyst towards the synthesis of functionalized small molecules via a tandem C-N, C-C bond forming reaction sequence. The development of two tandem sequential reactions will be described, as well as their applications in the synthesis of α-cyanoamines, α-amino acid derivatives, β-amino alcohols, diamines, imidazolidinones, and β-amino acid derivatives. These tandem reactions show an expanded substrate scope and increase synthetic flexibility by allowing for alternative starting materials in the preparation of highly functionalized small molecules. The second section describes progress towards the development of an asymmetric tandem reaction sequence, including investigations into the mode of activation for the tandem reaction. It has been established that a nucleophilic activation mode is required to generate an active species for the C-C bond forming step. Furthermore, it is postulated that the coordination environment and steric congestion about the activator impacts reaction efficiency and stereoselectivity. This information will be valuable in the design of future generations of activators. The final section reports the development of two novel group 4 metal complexes for catalytic hydroamination. The synthesis and full characterization of these complexes will be described, as well as the results of the catalytic investigations. Through this investigation it has been postulated that while a change in the electronic nature of the metal complex does enhance catalytic reactivity, the degree of orbital overlap between the ligand and the metal center is also an important consideration in the design of electrophilic hydroamination precatalysts. Hydroamination catalysis is currently an attractive area of intense research. The work in this thesis has demonstrated the use of hydroamination catalysis in the synthesis of highly functionalized small molecules, and has furthered the fundamental understanding of the hydroamination reaction. This increase in understanding can then be applied towards the rational design of more powerful hydroamination catalysts and further their application in the synthesis of functionalized N-containing compounds.Science, Faculty of
Chemistry, Department of
Graduate
12
Kilaru, Praveen. "New Strategies for Transition Metal Catalyzed C-C and C-N Bond Formation." Diss., North Dakota State University, 2018. https://hdl.handle.net/10365/31710.
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Transition metal catalysis emerged as an essential tool in the field of organic chemistry. In this context, transition metal catalyzed C-H bond functionalization is considered as an alluring strategy as it occurs with the high atom-and-step economy. In the recent years, significant attention has been paid for the conversion of C-H bond into C-X (X = C, N, O, S, P..etc) bonds using transition metal catalysts. This thesis presents the development of new catalytic systems for the construction of C-C and C-N bonds through late transition metal-mediated C-H activation and decarboxylation reactions. Chapter 1 introduces the background of transition metal catalyzed C-H bond functionalization. This chapter provides reported catalytic methods for the conversion of arene C-H bonds into various functional groups through transition metal mediated chelation-assisted C-H bond activation.
Chapter 2 describes the development of a new method for the synthesis of oxindoles via intramolecular alkene hydroarylation with N-aryl acrylamides using a Ru(II)/N-heterocyclic carbene (NHC) catalyst system. This reaction occurs with good substrate scope and synthetically useful tolerance of functional groups and does not require the assistance of additional directing group. Preliminary mechanistic results support a tandem sequence involving amide-directed aromatic C-H bond activation and intramolecular alkene arylmetalation. Chapter 3 describes ruthenium-based decarboxylative alkenylation of heteroarenes through carboxylate directed C-H bond functionalization. The decarboxylative functionalization of heteroarenes occurs with high regioselectivity and a broad range of functional group tolerance. This decarboxylation proceeds without stoichiometric amounts of bases or oxidants and it is applicable for functionalization of various heteroarenes such as indole, pyrrole, thiophene, benzothiophene, and benzofuran at both C-2 and C-3 positions. The current protocol provides a straightforward approach for the synthesis of trisubstituted olefins with heteroarenes. Chapter 4 explains the development of Rh/Ag-bimetallic catalyst system for decarboxylative amidation of ortho-substituted benzoic acids with 3-aryldioxazolones. The nature of ortho-substituents determines regioselectivity of this reaction through two forms of proposed chelation assistance: (1) A wide range of non-directing ortho-substituents led to ortho-amidation products via carboxylate-directed C-H amidation and subsequent decarboxylation. (2) 2-Pyridyl and analogous DGs led to ipso-amidation products via DG-assisted decarboxylation and subsequent amidation.
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Kumar, T. S. "Enantioselective synthesis of bioactive molecules using asymmmetric oxidations and synthetic methodologies involving formation of C-N,C-O and C-Br bonds." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2007. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2556.
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Snell, Robert Henry. "Development and application of asymmetric C-N bond formation." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:512e617a-2b01-45f3-86ae-c0cf4b874149.
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A synthetic investigation on the chemistry of cyclotryptamine derived natural products, with a particular focus on the synthesis of the trimeric-alkaloid, hodgkinsine. Methodology has been developed to tackle this complex natural product which utilises a desymmetrization approach; this strategy hinges on the development and applications of asymmetric C-N bond forming reactions. Chapter one examines elements of symmetry in natural products, looking in particular at the synthesis of compounds which contain cyclotryptamine functionality. Chapter two contains a brief review of enantioselective desymmetrization paying attention, if possible, on its application in the synthesis of natural products. In the remaining chapters we discuss our own progress and results in our pursuit of an efficient enantioselective total synthesis of hodgkinsine.
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Dabb, Serin Lloyd Chemistry Faculty of Science UNSW. "Hydrazine in late transition metal-mediated N-C bond formation." Publisher:University of New South Wales. Chemistry, 2008. http://handle.unsw.edu.au/1959.4/41428.
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This thesis describes investigations into the metal-mediated formation of nitrogen-carbon bonds from hydrazines and alkynes. Rh, Ir, Ru and Os metal complexes containing bidentate P,N- and N,N-donor ligands were all studied during the course of this work. A series of stereoisomers of metal complexes of general formula MCl2(PyP)2 (where M = Ru and Os, PyP = 1-(2-(diphenylphosphino)ethyl)pyrazole) (2.01-2.05) were synthesised. The isomerisation process of complexes 2.01-2.05 in solution was investigated. The ruthenium complex RuCl2(CO)(1-P-PyP)(2-P,N-PyP) (2.14), which contains one pendant PyP ligand bound through the P-donor ligand was synthesised, confirming the potential hemilability of the mixed P,N-donor ligand PyP. Chloride abstraction from the ruthenium complex trans,cis,cis-RuCl2(PyP)2 (2.01) was achieved using either a sodium or silver salt to yield the dimeric complexes of general formula [Ru(μ-Cl)(PyP)2]2[X]2 (where M = Ru, X = OSO2CF3 (2.06), BF4 (2.07), BPh4 (2.08), and BArF 2.09). [Os(μ-Cl)(PyP)2]2[BPh4]2 (2.10) was synthesised from sodium tetraphenylborate and trans,cis,cis-OsCl2(PyP)2 (2.04). The reactivity of dimeric complexes 2.06 and 2.08 towards substituted hydrazines was investigated. The methylhydrazine complex [Ru(PyP)2(NH2NHMe)][Cl][BPh4] (3.12) was synthesised. The methylhydrazine adduct of 3.12 binds to the metal centre in an end-on fashion via the NH2 group in solution, and in a bidentate fashion in the solid-state. This is the first reported example of a ruthenium complex containing a bidentate hydrazine ligand. The ruthenium-vinylidene complexes [RuCl(Me2PyP)2(=C=C(H)Ph)]BPh4 (4.15) and [RuCl(Me2PyP)2(=C=C(H)n-Bu)]BPh4 (4.16) (Me2PyP = 1-(2-(diphenylphosphino)ethyl)-3,5-dimethylpyrazole) were synthesised from trans,cis,cis-RuCl2(Me2PyP)2 (4.10) and the appropriate terminal alkyne. The reaction of alkynes with ruthenium complexes containing the PyP ligand was also investigated. Nitrogen-carbon bond formation was achieved through reaction of mono-substituted hydrazines with 4.06 and 4.07 to yield complexes of general formula [RuCl(1-P-Me2PyP)(2-P,N-Me2PyP)(2-N,C-(NH2N(R2)C(CH2R1)]BPh4 (where R1 = R2 = Ph (4.19), R1= Ph, R2 = Me (4.20), R1 = n-Bu, R2 = Ph, (4.21) or R1 = n-Bu, R2 = Me (4.22)). The mechanism of the formation of the stable metallocyclic complexes 4.19-4.22 was elucidated through studies of the reactivity of 4.15 towards a series of amines and hydrazines and relies on the labile nature of the N-donor of the P,N-donor ligand Me2PyP. A method for the synthesis of triflate complexes of rhodium Rh(PyP)(CO)(OSO2CF3) (5.13) and Rh(PyPhP)(CO)(OSO2CF3) (PyPhP = 1-(2-(diphenylphosphino)phenyl)pyrazole) (5.14) from rhodium chloride complexes was developed. The solid-state structure of rhodium triflate complex 5.14, which contained the more sterically rigid ligand PyPhP, exhibited a much greater distortion from the ideal square planar geometry than the rhodium analogue 5.13 which contains the PyP ligand. The triflate group of 5.13 and 5.14 was displaced by substituted hydrazines to yield new hydrazine complexes of rhodium. A series of Rh and Ir complexes with bidentate P,N- and N,N-donor ligands were found to catalyse the intermolecular hydroamination of alkynes with hydrazines. [Ir(bpm)(CO)2]BArF (6.08) was found to be the most efficient catalyst of those studies for this transformation, and was amongst the most efficient catalysts reported to date for this transformation. The influence of counter-ion was highly significant in the catalysed intermolecular hydroamination reaction. The substrate scope of the intermolecular hydroamination of alkynes with hydrazines was investigated using [Ir(bpm)(CO)2]BArF (6.08) as the catalyst.
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Jiang, Tuo. "Palladium(II)-Catalyzed Oxidative Carbocyclization : Stereoselective Formation of C–C and C–B Bonds." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-108669.
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Transition metal catalysis has emerged as one of the most versatile methods for the selective formation of carbon–carbon and carbon–heteroatom bonds. In particular, oxidative carbon–carbon bond forming reactions have been widely studied due to their atom economic feature. This thesis has been focused on the development of new palladium(II)-catalyzed carbocyclization reactions under oxidative conditions. The first part of the thesis describes the palladium(II)-catalyzed oxidative carbocyclization-borylation and -arylation of enallenes. In these reactions, the (σ-alkyl)palladium(II) intermediate, which was shown previously to undergo β-hydride elimination, could be trapped in situ by organoboron reagents (B2pin2 and arylboronic acids) to form new carbon–boron and carbon–carbon bonds. Through these two protocols, a range of borylated and arylated carbocycles were obtained as single diastereomers in high yields. The second part deals with a palladium(II)-catalyzed oxidative diarylative carbocyclization of enynes. The reaction was proposed to start with a syn-arylpalladation of an alkyne, followed by insertion of the coordinated alkene. Subsequent arylation afforded a series of valuable diarylated tetrahydrofuran and tetrahydropyran products. The final part of the thesis advances the previously developed palladium(II)-catalyzed oxidative carbocyclization-borylation of enallenes in an enantioselective manner. C2-symmetric chiral phosphoric acids were used as the novel co-catalyst to trigger the enantioselective formation of intramolecular carbon–carbon bonds. By using this chiral anion strategy, a number of enallenes were converted to the borylated carbocycles with high to excellent enantioselectivity.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.
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Akana, Jennifer Anne. "Catalytic C-N and C-F bond formation by organometallic group 11 complexes." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39585.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2007.Vita.
Includes bibliographical references.
This thesis presents a study of the reaction between an (NHC)gold(I) fluoride complex (NHC = N-heterocyclic carbene) and alkynes (Chapter 1). Gold(I) and fluoride add trans across the triple bond of 3-hexyne and 1-phenyl-l-propyne to form (fluorovinyl)gold(I) complexes, with exclusive geminal arrangement between the phenyl group and gold in the latter case. This addition is reversible, and the (fluorovinyl)gold(I) complexes can extrude alkyne to return (NHC)gold(I) fluoride. Treatment of (fluorovinyl)gold(I) complexes with strong acid protonates the vinylic group with strong acid to afford trans-hydrofluorination. The same fluoroalkene product is obtained by treatment of an (1i2-alkyne)gold(I) complex with the mild HF source Et3N.3HF. Cationic (NHC)gold(I) complexes catalyze the trans-hydrofluorination of internal alkynes with Et3N*3HF (Chapter 2). Sterically demanding, electrophilic supporting ligands and the presence of acid buffers improve reaction efficiency. A study of aryl-substituted alkynes suggests that electron-poor aryl groups favor shorter reaction times and higher regioselectivity of fluorination. A heavily fluorinated phenanthroline ligand supporting a cationic copper(I) catalyst allows efficient functionalization of C-H bonds using sulfonyl azides (Chapter 3).
(cont.) Performing the reaction in 1,1,1,3,3,3-hexafluoroisopropanol solvent is crucial. The intramolecular cyclization of sulfonyl azides through nitrene insertion into proximate benzylic or aliphatic C-H bonds is established, and efficient intermolecular arene amidation was achieved. The best yields result from using electron-rich substrates and electron-poor azides. A small kinetic isotope effect measured for the amidation of benzene indicates that C-H bond activation is probably not the rate-determining step. The presence of a 1,2-shift is consistent with an electrophilic mechanism for arene activation. The formation of both aryl- and benzyl-substituted products from mesitylene indicates that different reaction pathways may compete in the electrophilic amidation process.
by Jennifer Anne Akana.
Ph.D.
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Berges, Julien. "Formation de liaisons C-C et C-N par catalyse au Cuivre, au Fer ou en absence de metal de transition." Thesis, Montpellier, Ecole nationale supérieure de chimie, 2016. http://www.theses.fr/2016ENCM0014.
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Le sujet de cette thèse se situe dans le cadre général des arylations de nucléophiles catalysées par des complexes de métaux de transitions (Cu, Fe) ou réalisées en absence de ces derniers, dans des conditions compétitives et respectueuses de l’environnement. Ces réactions sont d’une importance majeure pour l’industrie chimique. Dans un premier chapitre est tout d’abord décrit un couplage inédit mettant en jeu un sel d’aryldiazonium et un nucléophile azoté (formation de liaison CAr-N). La méthode procède dans des conditions douces via un système catalytique au cuivre peu coûteux et peu toxique. Les produits de couplage obtenus (Ar-NHet) sont d’un intérêt central dans l’industrie pharmaceutique et agrochimique. Dans une deuxième partie nous avons présenté une méthode permettant de réaliser le couplage entre des sels d’aryldiazonium et des dérivés du styrène, à l’aide d’un système t BuOK/DMF. Cette réaction, réalisée pour la première fois en absence de catalyseurs à base de métaux de transition, permet d’accéder, via la formation de liaisons CArsp²-Csp², à des motifs stilbènes variés qui trouvent de nombreuses applications en chimie pharmaceutique. Un deuxième chapitre porte sur l’utilisation de dérivés de l’iode hypervalent permettant la fonctionnalisation de noyaux aromatiques (C-H) ou de dérivés vinyliques (C-H). Une première méthode décrit une réaction de triflimidation directe de composés acétanilides avec une sélectivité exclusive en position para. Deux conditions réactionnelles ont été mises en place pour cette fonctionnalisation. Une première utilise une quantité stœchiométrique de PhI(OAc)2 et une autre utilise une quantité catalytique d’iodotoluène (génération in-situ de l’iode(III)). Cette transformation a conduit à la formation de liaisons CAr-N en présence de bis(trifluorométhane)sulfonimide de lithium (LINTf2) comme nucléophile azoté. Dans une deuxième partie, nous avons montré que l’iodure de bisphosphoranilidène (PNPI), pouvait catalyser la trifluorométhylation vinylique sélective de dérivés du styrène en présence d’un réactif de l’iode hypervalent (l’iode(III)), le réactif de Togni II. Des travaux sont en cours pour tenter de comprendre l’influence positive de l’utilisation de PNPI dans le cas de notre réaction. Un troisième chapitre décrit des résultats préliminaires permettant d’obtenir un rendement honorable (54%) lors du couplage catalysé au fer du 4-iodotoluène avec le phényllithium. Une autre série de test décrit le couplage entre des halogénures d’aryle et des alkyllithium primaires. La méthode semble très efficace, puisque par ailleurs les travaux très récents de la littérature pour des couplages similaires faisant intervenir les mêmes partenaires réactionnels, font appel à des catalyseurs de fer ou de palladiumThis thesis is part of a very general search seek to develop methodologies for environmentally sustainable conversion of small molecules into more valuable substances catalyzed by copper and iron complexes or under metal-free conditions. The work focuses on the functionalization of aromatic rings by C-C or C-N bond formation.In a first chapter, a novel coupling involving an aryldiazonium salt and a nitrogenous nucleophile (CAr-N bond formation) is first described. The method proceeds under mild conditions using a cheap and non-toxic copper catalyst system. The obtained coupling products (Ar-NHet) are of central interest in the pharmaceutical and agrochemical industry. Then in a second part, a method allowing the coupling between aryldiazonium salts and styrene derivatives, using a BuOK / DMF system is presented. This reaction, carried out for the first time in the absence of catalysts based on transition metals, makes it possible to access to various stilbene units which find numerous applications in pharmaceutical chemistry.A second chapter concerns the use of hypervalent iodine derivatives allowing the functionalization of aromatic or vinyl substrates. A first method describes a direct triflimidation reaction of acetanilide compounds with an exclusive selectivity in the para position. Two reactions conditions have been established for this functionalization. One uses a stoichiometric amount of PhI(OAc)2 and another uses a catalytic amount of iodotoluene (in-situ generation of iodine (III)). This transformation resulted in the formation of CAr-N bonds in the presence of lithium bis (trifluoromethane) sulfonimide (LINTf2) as the nitrogen nucleophile. In a second part, we have shown that bisphosphoranilidene iodide (PNPI) can catalyze a selective vinylic trifluoromethylation of styrene derivatives in the presence of a hypervalent iodine reagent (iodine (III)), Togni’s reagent II. Work is under way to try to understand the positive influence of PNPI.A third chapter describes preliminary results of an iron-catalyzed heterocoupling of 4-iodotoluene an phenylithium system allowing the obtention of an honorable yield (54%) during the coupling of 4-iodotoluene with phenyllithium. Another series of tests describes the coupling between aryl halides and primary alkyllithiums. The method seems to be very effective, since very recent work in the literature for similar couplings involving the same reaction partners involves catalysts of iron or palladium
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Park, Nathaniel H. (Nathaniel Hamilton). "Development of new transition metal catalysts for C-N bond formation and continuous flow processes for C-F bond formation." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101553.
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Thesis: Ph. D. in Organic Chemistry, Massachusetts Institute of Technology, Department of Chemistry, 2015.Cataloged from PDF version of thesis. Vita.
Includes bibliographical references.
The work presented in this dissertation addresses the development of new methodologies and processes to form carbon-nitrogen (C-N) and carbon-fluorine (C-F) bonds. The development of methods for the formation of C-N and C-F bonds are highly important to chemistry in general and find broad application in many different areas of research. With regard to C-N bond formation, the development of new nickel and palladium catalyst for C-N cross-coupling is presented. Finally, the development of a new process to enable the rapid preparation of aryl fluorides via the Balz-Schiemann reaction is explored. Chapter 1. Development of an Air-Stable Nickel Precatalyst for the Amination of Aryl Chlorides, Sulfamates, Mesylates, and Triflates. A new air-stable nickel precatalyst for C-N cross-coupling is reported. The developed catalyst system displays a greatly improved substrate scope for C-N bond formation to include both a wide range of aryl and heteroaryl electrophiles and aryl, heteroaryl, and alkyl amines. The catalyst system is also compatible with weak base, allowing for the amination of substrates containing base-sensitive functional groups. Chapter 2. Design of New Ligands for the Palladium-Catalyzed Arylation of a- Branched Secondary Amines. In Pd-catalyzed C-N cross-coupling reactions, a-branched secondary amines are difficult coupling partners and often produce low yields of the desired product. To provide a robust method for accessing N-aryl a-branched tertiary amines, new catalysts have been designed to suppress undesired side reactions often encountered when these amine nucleophiles are used. These advances enabled the arylation of a wide array of sterically encumbered amines, highlighting the importance of rational ligand design in facilitating challenging Pd-catalyzed cross-coupling reactions. Chapter 3. Rapid Synthesis of Aryl Fluorides in Continuous Flow via the Balz- Schiemann Reaction. The synthesis of aryl fluorides (ArF) is of critical importance for the development of new and potent pharmaceuticals and agrochemicals. While there have been numerous and intense research efforts focused on developing new fluorination methods, the Balz-Schiemann reaction remains a valuable and efficient means of aryl C-F bond construction from a vast pool of available aryl amines. However, the harsh reaction conditions, modest yields, and often prohibitive safety concerns have limited the general application of this methodology. Here, we have developed a semi-flow process that enables safe handling of the potentially explosive aryl diazonium salt intermediates as well as improved yields of the desired aryl fluoride products. This process has been demonstrated on an array of different aryl and heteroaryl amine substrates containing a variety of different functional groups.
by Nathaniel H. Park.
Ph. D. in Organic Chemistry
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Dabrowski, Jennifer A. "Development of Selective Methods to Form C-C Bonds. Enantioselective Formation of Tertiary and Quaternary Stereogenic Centers." Thesis, Boston College, 2013. http://hdl.handle.net/2345/3771.
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Thesis advisor: Amir H. HoveydaFormation of C-C bonds is an invaluable tool for the construction of materials, pharmaceuticals, natural products, and the building blocks of life. Although great strides in this area have been made, there remain several limitations in regio-, site-, and enantioselective additions of carbon-based nucleophiles. Solving these challenges by expanding the scope, efficiency, and selectivity of alkyl, aryl, heteroaryl, vinyl, and alkynyl additions to carbon-based electrophiles is the topic of this dissertation
Thesis (PhD) — Boston College, 2013
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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Bosnidou, Alexandra Eleni. "New Methodology for C-N Bond Formation within Iodine Redox Manifolds." Doctoral thesis, Universitat Rovira i Virgili, 2019. http://hdl.handle.net/10803/668478.
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Els últims desenvolupaments en el camp de la construcció d’enllaços carboni-nitrogen es mostren en aquesta tesi doctoral. En aquesta, es revelen alternatives més verdes a les metodologies sintètiques comunes, amb l’ús de reactius de iode hipervalent i iode molecular com a principals promotors.
Inicialment, es presenta l’ús de reactius de iode hipervalent definits que promouen l’aminació C-H selectiva i directa del nucli indol de diferents tipus de triptamines. Començant per l’aminació general, transformacions posteriors, com la iodació, fluoració, etc. es van realitzar per tal de rendir productes més funcionalitzats, amb una quimioselectivitat remarcablement alta. Per tant, s’ha fet disponible un major grau de diversificació estructural per als derivats triptamínics, proveint blocs de construcció (building blocks) que obren espai químic per a més exploració.
Seguidament, es discuteix l’aminació catalítica fotoquímica d’arens. La reacció es dóna en catàlisi de iode i presència de llum visible com a iniciador, i permet l’accés a un ventall d’aril amines substituïdes. L’ampli abast de la reacció es va poder expandir encara més a derivats bloquejats amb grups silil, que experimenten una aminació intramolecular per tal de donar lloc a heterocicles de set membres. L’escissió del grup silil permet l’accés a les corresponents anilines 3-substituïdes.
L’aminació directa d’enllaços C-H alifàtics ha estat una de les transformacions més desafiants en la química orgànica. En la última part de la tesi, reportem l’esmunyedissa aminació C(sp3)-H sota un sistema catalític únic, basat en la recentment desenvolupada aminació intramolecular. Aquesta estratègia sintètica pràctica permet l’accés a blocs de construcció aminats. És presentada també una extensió que fomenta múltiples aminacions C-H per a aconseguir heterocicles aminats. La utilitat sintètica de la metodologia és demostrada per la síntesi de quatre productes farmacèutics rellevants.En esta Tesis Doctoral se describen los últimos avances en el campo de la construcción de enlaces carbono-nitrógeno. En ella se discuten alternativas más verdes, comparadas con las metodologías más comunes, mediante el uso de reactivos hipervalentes de yodo y yodo molecular como principales promotores. En la primera sección se presenta el uso de reactivos hipervalentes de yodo que promueven la aminacion C-H directa y selectiva del grupo indol en varios derivados de triptamina. A partir de esta aminación general, otras transformaciones, tales como iodinación, fluorinación, etc. fueron llevadas a cabo, obteniendo productos altamente funcionalizados con una remarcable alta quimioselectividad. De este modo, una alta diversificación estructural de derivados de triptamina están disponibles, proveyendo diferentes componentes que permiten futuras exploraciones en este área. En la siguiente sección, se describe la aminación fotoquímica y catalítica de arenos. Esta reacción funciona mediante catálisis de yodo molecular en presencia de luz visible como iniciador, dando acceso a un amplio rango de arilaminas con diferentes patrones de substitución. Esta metodología es muy general y puede expandirse a derivados con silicio que dan lugar a heterociclos de siete miembros. La ruptura de este enlace silicio-carbono da acceso a las correspondientes anilinas meta-subtituidas. La aminación directa de enlaces C-H alifáticos es una de las transformaciones más dificiles de conseguir en química orgánica. En la última parte de esta Tesis se describe la aminación intermolecular de C(sp3)-H basada en la recientemente desarrollada versión intramolecular. Esta estrategia sintética permite el acceso a diferentes estructuras aminadas de importancia. También se presenta la extensión de esta metodología hacia la aminacion de multiples C-H, obteniendo aza-heterociclos. La utilidad práctica de esta metodología esta demostrada mediante la síntesis de cuatro compuestos de interés farmacéutico
The latest developments in the field of oxidative carbon-nitrogen bond construction are represented in this Doctoral Thesis. Greener alternatives to established synthetic methodologies have been disclosed with the use of hypervalent iodine reagents and molecular iodine as main promoters. Initially, the use of defined hypervalent iodine reagents that promote the selective direct C-H-amination at the indole core of various tryptamines is presented. Starting from the general amination, subsequent transformations, such as iodination, fluorination etc. were performed to afford higher-functionalized products with a noteworthy chemoselectivity. Consequently, a higher degree of structural diversification has become available for tryptamine derivatives, providing building blocks that open chemical space for further exploration. Subsequently, a photochemical catalytic amination of arenes is discussed. The reaction proceeds under benign iodine catalysis in the presence of visible light as the initiator and provides access to a range of differently substituted arylamines. The broad scope of the reaction could further be expanded to silyl-tethered derivatives, which undergo intramolecular amination to give rise to seven-membered heterocycles. Cleavage of the silicon tether provides access to the corresponding 3-substitued anilines. The direct amination of aliphatic C-H bonds has remained one of the most challenging transformations in organic chemistry. In the last part of this thesis, the elusive intermolecular C(sp3)-H amination based on a unique homogeneous iodine catalyst system is reported. This practical synthetic strategy allows the access to aminated building blocks. An extension that fosters innovative multiple C-H amination toward aminated heterocycles is also presented. The synthetic utility of the methodology is demonstrated by the synthesis of four relevant pharmaceuticals.
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Sung, Simon. "Understanding of Cu-catalysed coupling reactions for C-N bond formation." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/51150.
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The rate of reaction for the copper-catalysed coupling reactions to form C–N bonds between aryl halides and amines can be significantly improved in the presence of various bidentate ligands. This improved reaction is often referred as the modified Ullmann amination reaction. However the intermediates and steps involved in the mechanism and the role of the ligand are not fully understood. In this work, mechanistic studies have been carried out in order to improve the current understanding of this reaction. The role of copper(I) alkylamide complexes as potential intermediates in the modified Ullmann reaction between aryl halides and alkylamines is discussed in Chapter 2. A series of copper(I) alkylamide complexes have been synthesised and shown using single crystal X-ray crystallography to exist as tetramers in the solid state. The structures of these complexes in benzene-d6 were determined by 1H DOSY NMR spectroscopy which revealed equilibrating aggregates, where the equilibrium rate could be faster or slower than the NMR time scale, with average aggregation numbers between the dimeric and tetrameric forms. The complexes have been shown to react stoichiometrically with iodobenzene to give arylamine products, both in the absence and presence of 1,10-phenanthroline as an ancillary ligand. The influence of 1,10-phenanthroline on the solution structures in benzene-d6 and DMSO-d6 is also discussed and can be related to the stoichiometric and catalytic reactivity. Overall these results highlight the role of copper(I) alkylamide complexes as potential intermediates and show the significance of 1,10-phenanthroline in modulating the reactivity of the system. Chapter 3 describes the improvement in product yield from utilising O,O- and N,O-chelating ligands over N,N-chelating ligands in the copper-catalysed C–N cross-coupling reaction between piperidine and iodobenzene. A kinetic study of this reaction using 2-acetylcyclohexanone as the added ligand demonstrated that the poorly soluble potassium phosphate base caused the reaction rate to be limited by mass transfer effects. The results provide insights into the qualitative rate dependences in the reactants and also the role of the ligand in the catalyst deactivation pathway by disproportionation. A mechanistic study of the copper-catalysed C–N cross-coupling reaction between piperidine and iodobenzene using bis(tetra(n-butyl)phosphonium) malonate as a soluble base is presented in Chapter 4. A detailed kinetic study using reaction calorimetry and the reaction progress kinetic analysis (RPKA) methodology reveals first order rate dependences in the substrates and copper catalyst concentration, and negative first order kinetics in the base concentration. NMR spectroscopic evidence suggests the malonate base simultaneously functions as an ancillary ligand and coordinates to give an off-cycle unstable species. Catalyst deactivation by disproportionation was found to be an important consequence of malonate ligand coordination, with the piperidine substrate playing a key role in mitigating the rate of catalyst deactivation. The absence of aryl radical formation suggests that the aryl halide activation mechanism occurs by an oxidative addition process. The experimental data has been successfully modelled to the proposed mechanism to give approximate equilibrium and rate constants for each step.
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Iglesias, Alvaro. "Defined transition metal complexes for catalytic oxidative C-N bond formation." Strasbourg, 2009. http://www.theses.fr/2009STRA6280.
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Cette thèse traite du développement de procédés employant des métaux de transition pour la formation de liaisons C-N. Dans ce but, trois axes de recherche sont décrits : (1) L’activation de dérivés azotés pour une aryl-amination sous catalyse concomitante au Pd(0)/Pd(II). (2) L’utilisation de catalyseurs d’or pour diamination oxydante d’alcènes qui a permis le développement d’une catalyse Au(I)/Au(III). Ces recherches ont conduit à des expériences stoechiométriques sur la faisabilité de l’oxydation de complexes d’or(I). (3) Ce travail a été étendu à l’étude de voies de synthèses réductrices de liaisons C-N à partir de complexes amidato-Pd(II) en conditions oxydantesThis thesis deals with the development of transition metal based processes for C-N bond formation. To this end, it describes three different areas of research, the activation of azo-compounds for a concomitant aryl-amination under Pd(0)/Pd(II) catalysis, secondly, the use of gold catalysts for an oxidative diamination of alkenes led to the development of Au(I)/Au(III) catalysis. The latter process gave rise to stoichiometric experiments on the feasibility of oxidation of gold(I) complexes. This work was equally extended to investigate pathways of reductive C-N bond formation from Pd(II)-amidato complexes under oxidative conditions
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Cai, Yingxiao. "Cobalt-catalyzed carbon-carbon bond formation by activation of carbon-halogen or carbon-hydrogen bonds." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX039/document.
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Ce travail de thèse présente le développement de nouvelles réactions de formation de liaisons carbone-carbone. Le premier chapitre décrit la cyanation d’arylzinciques par catalyse au cobalt à partir d’une source non toxique et bénigne, le N-cyano-N-phenyl-p-methylbenzenesulfonamide (NCTS), et conduit à de bons rendements en benzonitriles correspondants. Dans cette réaction, le cobalt sert de catalyseur non seulement pour la formation des arylzinciques mais aussi pour la formation de liaisons C-CN. Les groupements fonctionnels, cétone et nitrile, sont permis lorsque le complexe de cobalt associé au ligand bipyridine est utilisé. Le deuxième chapitre porte sur l’homocouplage Csp3-Csp3. Un simple halogénure de cobalt permet de catalyser la dimérisation des halogénures d’alkyles et des acétates d’allyles avec de bons à d’excellents rendements. L’ajout d’iodure de sodium permet d’étendre cette réaction aux chlorures et tosylates d’alkyles. Le couplage croisé entre 2 halogénures d’alkyle différents a également été testé mais les conditions doivent être optimisées. Dans le troisième chapitre, le couplage croisé catalysé au cobalt entre des bromures vinyliques et des chlorures benzyliques est présenté. Des halogénures de vinyles et de benzyles porteurs de groupements electrodonneurs ou electroattrateurs peuvent ainsi être couplés efficacement avec rétention de la configuration de la double liaison. Un mécanisme radicalaire semble être impliqué. Enfin, le dernier chapitre décrit l’arylation d’une 2-phenylpyridine avec un arylzincique par catalyse au cobalt par activation d’une liaison C-H et conduit à de premiers résultats encourageantsThis thesis presents the development of cobalt-catalyzed carbon-carbon bonds formation. The first chapter describes a novel cobalt-catalyzed electrophilic cyanation of arylzinc species, employing benign and non-toxic N-cyano-N-phenyl-p-methylbenzenesulfonamide (NCTS) as the cyano source. In this reaction, cobalt catalyzes both the formation of arylzinc species and the cyanation reaction. Various benzonitriles are synthesized affording good to excellent yields. Using cobalt-bipyridine complexes instead of CoBr2, ketone and nitrile groups can be tolerated. The second chapter reports cobalt-catalyzed Csp3-Csp3 homocoupling reaction. A simple catalytic system could deliver dimers of a number of alkyl halides/pseudohalides and allylic acetates. Sodium iodide is crucial for the homocoupling of unactivated alkyl chlorides and tosylates. This method is extended to alkyl-alkyl cross-coupling; however, the conditions still need to be optimized. The third chapter describes a cobalt-catalyzed vinyl-benzyl cross-coupling. A variety of functionalized vinyl bromides and benzyl chlorides are efficiently coupled under mild conditions in good to excellent yields, with retention of Z/E configuration. A few mechanistic experiments indicate a single electron transfer involved. The last chapter discusses the progress on the cobalt-catalyzed arylation of 2-phenylpyridine with an arylzinc species by C-H activation and promising results are obtained
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Lin, Xufeng. "Density functional theory studies of selected transition metals catalyzed C-C and C-N bond formation reactions." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B39359645.
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Lin, Xufeng, and 林旭鋒. "Density functional theory studies of selected transition metals catalyzed C-C and C-N bond formation reactions." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39359645.
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Vuong, Khuong Quoc Chemistry Faculty of Science UNSW. "Metal complex catalysed C-X (X = S, O and N) bond formation." Awarded by:University of New South Wales. Chemistry, 2006. http://handle.unsw.edu.au/1959.4/23015.
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This thesis describes the catalysed addition of X-H bonds (X = S, O and N) to alkynes using a range of novel rhodium(I) and iridium(I) complexes containing hybrid bidentate phosphine-pyrazolyl, phosphine-imidazolyl and phosphine-N heterocyclic carbene (NHC) donor ligands. The synthesis of novel bidentate phosphine-pyrazolyl, phosphine-imidazolyl (P-N) and phosphine-NHC (PC) donor ligands and their cationic and neutral rhodium(I) and iridium(I) complexes [M(P N)(COD)]BPh4, [M(PC)(COD)]BPh4, [Ir(P-N)(CO)2]BPh4 and [M(P-N)(CO)Cl] were successfully performed. An unusual five coordinate iridium complex with phosphine-NHC ligands [Ir(PC)(COD)(CO)]BPh4 was also obtained. Seventeen single crystal X-ray structures of these new complexes were determined. A range of these novel rhodium and iridium complexes were effective as catalysts for the addition of thiophenol to a variety of alkynes. Iridium complexes were more effective than rhodium analogues. Cationic complexes were more effective than neutral complexes. Complexes with hybrid phosphine-nitrogen donor were more effective than complexes containing bidentate nitrogen donor ligands. An atom-economical, efficient method for the synthesis of cyclic acetals and bicyclic O,O-acetals was successfully developed based on the catalysed hydroalkoxylation. Readily prepared terminal and non-terminal alkyne diols were cyclised into bicyclic O,O-acetals in quantitative conversions in most cases. The efficiency of a range of rhodium and iridium complexes containing bidentate P-N and PC donor ligands as catalysts for the cyclisation of 4-pentyn-1-amine to 2-methyl-1-pyrroline varied significantly. The cationic iridium complexes with the bidentate phosphine-pyrazolyl ligands, [Ir(R2PyP)(COD)]BPh4 (2.39-2.42) were extremely efficient as catalysts for this transformation. Increasing the size of the substituent on or adjacent to the donor led to improvement in catalytic activity of the corresponding metal complexes. The mechanism of the catalysed hydroalkoxylation was proposed to proceed by the initial activation of the alkyne via ?? coordination to the metal centre. The ?? binding of both aliphatic and aromatic alkynes to [Ir(PyP)(CO)2]BPh4 (2.44) was observed by low temperature NMR and no reaction between 2.44 and alcohols was observed. In contrast, the facility in which thiol and amine oxidatively added to 2.44 led the proposal that in the hydrothiolation and hydroamination reaction, the catalytic cycle commences with the activation of the X-H bond (X = S, N) by an oxidative addition process.
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Zhao, Tony. "Synthesis of functionalized allylic, propargylic and allenylic compounds : Selective formation of C–B, C–C, C–CF3 and C-Si bonds." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-116863.
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This thesis is focused on the development of new palladium and copper- mediated reactions for functionalization of alkenes and propargylic alcohol derivatives. The synthetic utility of the 1,2-diborylated butadienes synthesized in one of these processes has also been demonstrated. We have developed an efficient procedure for the synthesis of allenyl boronates from propargylic carbonates and acetates. This was achieved by using a bimetallic system of palladium and copper or silver as co-catalyst. The reactions were performed under mild conditions for the synthesis of a variety of allenyl boronates. Furthermore, the synthesis of 1,2-diborylated butadienes was achieved with high diastereoselectivity from propargylic epoxides. The reactivity of the 1,2-diborylated butadienes with aldehydes was studied. It was found that the initial allylboration reaction proceeds via an allenylboronate intermediate. The allenylboronate reacts readily with an additional aldehyde to construct 2-ethynylbutane-1,4-diols with moderate to high diastereoselectivity. We have also studied the copper-mediated trifluoromethylation of propargylic halides and trifluoroacetates. It was also shown that a transfer of chirality occurred when an enantioenriched starting material was used. In the last part of the thesis, we have described a method for palladium-catalyzed functionalization of allylic C-H bonds for the selective synthesis of allylic silanes. The protocol only works under highly oxidative conditions which suggest a mechanism involving high oxidation state palladium intermediates.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 1: Accepted.
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Nikitin, Anton. "Hydrogen storage in carboneous materials through the formation of C-H bonds /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Bartoszewicz, Agnieszka. "Transition metal-catalysed hydrogen transfer processes for C-C and C-N bond formation : Synthetic studies and mechanistic investigations." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-81596.
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This thesis focusses on synthetic studies and mechanistic investigations into reactions involving hydrogen-transfer processes. In the first part, the development of an efficient method for the synthesis of β-hydroxy ketones (aldols) and β-amino ketones (Mannich products) from allylic alcohols and aldehydes is described. These reactions use Ru(η5-C5Ph5)(CO)2Cl as the catalyst. The reaction parameters were optimised in order to suppress the formation of undesired by-products. Neutral and mild reaction conditions enabled the synthesis of a variety of aldol products in up to 99% yield, with a good syn/anti ratio. The influence of the stereoelectronic properties of the catalyst on the reaction outcome was also studied. Based on the results obtained, a plausible reaction mechanism has been proposed, involving as the key steps the 1,4-addition of hydride to α,β-unsaturated ketones and the formation of ruthenium (Z)-enolates. In the second part of this thesis, a ruthenium-catalysed tandem isomerisation/C-H activation reaction is presented. A number of ruthenium complexes, phosphine ligands, and additives were evaluated in order to establish the optimal reaction conditions. It was found that the use of a stable ruthenium catalyst, Ru(PPh3)3Cl2, together with PtBu3 and HCO2Na resulted in an efficient tandem transformation. Using this procedure, a variety of ortho-alkylated ketones were obtained in excellent yields. Moreover, homoallylic alcohols could also be used as starting materials for the reaction, which further expands the substrate scope. Mechanistic investigations into the isomerisation part of the process were carried out. The last project described in the thesis deals with the design and preparation of novel bifunctional iridium complexes containing an N-(2-hydroxy-isobutyl)-N-Heterocyclic carbene ligand. These complexes were used as catalysts to alkylate amines using alcohols as latent electrophiles. The catalytic system developed here was found to be one of the most active systems reported to date, allowing the reaction to be performed at temperatures as low as 50 °C for the first time. A broad substrate scope was examined. Combined experimental and theoretical studies into the reaction mechanism are consistent with a metal-ligand bifunctional activity of the new catalyst.
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Peterson, Matt Anders. "Stereoselective synthesis of β-amino alcohols and glycosphingolipids: N-diphenylmethylene protection for tandem C-C/C-O bond formation." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/186053.
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A new method for threo-selective synthesis of β-amino alcohols is described. This method employs N-diphenylmethylene-protected α-amino esters as starting materials. The α-amino ester is reduced to the oxidation state of an aldehyde with DIBAL or DIBAL:TRIBAL (1:1) followed by sequential addition of various Grignards and alkenyllithiums. The method is highly threo-selective (stereoselectivities ranged from 8:1 to > 20:1) and provides norpseudoephedrine and threo-sphingosine analogs in enantiomerically enriched form (> 97% ee). The mechanism of C-C bond formation was examined. A stable aluminoxy-acetal intermediate (generated by DIBAL reduction of the ester) was trapped with TMS-imidazole and isolated as the corresponding siloxy-acetal. The stereochemical outcome of the C-C bond forming step was shown to correlate with the steric bulk of the ester moiety. Bulky ester groups showed the greatest degree of threo-selectivity. These results suggest that the aluminoxy-acetal intermediate may be involved in determining stereoselectivity via either a tight-ion S(N)1-like or S(N)2-like reaction mechanism. A series of glycosyl acceptors was synthesized from N-diphenylmethylene-protected threo-sphingosine derivatives. These glycosyl acceptors undergo β-specific glycosylation using the method developed in this laboratory. This method capitalizes on a favorable hydrogen-bonding pattern imparted by the N-diphenylmethylene-protection. The favorable hydrogen-bonding enhances the nucleophilicity of the glycosyl acceptor relative to glycosyl acceptors with more conventional N-protection (i.e. Cbz, Boc, acyl etc.). This enhanced nucleophilicity allows the glycosylation to be carried out under mild conditions (AgOTfl, CH₂CI₂, RT overnight) and provides the corresponding β-glycosphingolipids in approximately 70% chemical yield.
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Ellis, Michael J. "Synthetic routes to polycyclic acridines : potential anti-tumour agents." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366289.
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Wu, Hao. "Catalytic Enantioselective Formations of C–B, C–C and C–Si Bonds by Organic Molecules or Transition-Metal Complexes." Thesis, Boston College, 2015. http://hdl.handle.net/2345/bc-ir:104759.
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Thesis advisor: Amir H. HoveydaCatalytic enantioselective reactions are of great importance in synthetic organic chemistry. Thus, development of efficient, selective and easily accessible catalyst for various bond formations is the main task in our laboratories. First, we have developed the first broadly applicable enantioselective boryl conjugate addition reactions to a variety of α,β-unsaturated carbonyls, promoted by a chiral Lewis basic N-heterocyclic carbene. The valuable β-boryl carbonyls were further used in complex molecule syntheses. The mechanism of these C–B bond formations was studied in details. We have also developed a practical method for enantioselective addition of an allene unit to aryl-, heteroaryl- and alkyl-substituted Boc-aldimines. These efficient C–C bond formations, catalyzed by an aminophenol-derived boron-based catalyst, were further utilized in succinct syntheses of anisomycin and epi-cytoxazone. Finally, chiral NHC–Cu complexes were employed for site-, diastereo- and enantioselective silyl conjugate additions to acyclic and cyclic dienones and dienoates. The precious enantiomerically enriched allylsilane obtained can be converted into a ketone-aldol type product, which is difficult to access through alternative methods
Thesis (PhD) — Boston College, 2015
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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Chakraborty, Rakesh Ranjan. "Explorative studies on carbon-nitrogen (C-N) bond formation and synthesis of nitrogen containing heterocyclic compounds." Thesis, University of North Bengal, 2018. http://ir.nbu.ac.in/handle/123456789/2798.
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Cheng, Hanchao Verfasser], Carsten [Akademischer Betreuer] [Bolm, and Dieter [Akademischer Betreuer] Enders. "Copper-Catalyzed N−H Functionalizations of NH-Sulfoximines for C−N Bond Formation / Hanchao Cheng ; Carsten Bolm, Dieter Enders." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1162499672/34.
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Cheng, Hanchao [Verfasser], Carsten [Akademischer Betreuer] Bolm, and Dieter [Akademischer Betreuer] Enders. "Copper-Catalyzed N−H Functionalizations of NH-Sulfoximines for C−N Bond Formation / Hanchao Cheng ; Carsten Bolm, Dieter Enders." Aachen : Universitätsbibliothek der RWTH Aachen, 2017. http://d-nb.info/1162499672/34.
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PALMIERI, Alessandro. "Study of Eco-Friendly Conditions and Processes in the Formation of New C-C Bonds by Stabilized Carbanions." Doctoral thesis, Università degli Studi di Camerino, 2007. http://hdl.handle.net/11581/401906.
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In the laboratory under the direction of Prof. Roberto Ballini (where I carried out my PhD work), an ''in-progress'' research project has been under way for the past few years. This project, in the field of eco-friendly chemical processes, aims to develop new synthetic methods which could reduce waste and guarantee cleaner reactions. In the team, my task involved studying new reduced environmental impact processes in C-C and C-X bonding. These new processes have been achieved through solid heterogeneous catalysis and domino reactions, and both these methods are in accordance with Green Chemistry guidelines ''Green Chemistry is the design of chemical products and processes that reduces or eliminates the use and generation of hazardous substances'' In this context, by means of solid heterogeneous catalysis, it is possible to reduce complicated work-up to a simple filtration or to a direct loading onto chromatographic column, avoiding the usage of aqueous layer, extraction with organic solvents and, above all, the application and the formation of salts, like Na2SO4 and NH4Cl. Further, the catalyst is weakly corrosive, shows very low toxicity, provides reaction without the use of any solvent (i.e. the most toxic element in a reaction) and, sometimes, it can be recycled. Domino reactions, defined as: ''the processes of two or more bond forming transformations under widely identical conditions in which the subsequent reactions take place at the functionalities obtained in the former transformation'', offer several advantages, in terms of environmental protection and lowering of costs, that lead to an advance toward eco-friendly systems. In fact, the possibility of producing two or more bonds in the same reaction conditions, instead of isolating every intermediate, diminishes the number of steps and consequently entails a reduction of work-up and purification processes. At the end, besides shortening the whole operation span, it provides a cut in the usage of solvents and reagents with evident decreasing of pollution. Thesis work As mentioned above, the main task of my PhD has been to cooperate to development of new synthetic processes in order to produce new C-C and C-X bonds under eco-friendly conditions. For this purpose aliphatic nitro compounds, thanks to the strong electron-withdrowing power of the nitro group, that guarantees the access using weak conditions to stabilized carbanions and the possibility of using the same group as leaving group, have proved to be good starting materials,compatible with low environmental impact processes.
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Yonson, Neal. "Bis(amidate) and bis(ureate) complexes of zirconium and tantalum : synthesis and catalytic application in C-N and C-C bond formation." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/45985.
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This is a study of early metal organometallic complexes for catalytic C-N and C-C bond formation using amines. The use of zirconium complexes as hydroamination catalysts is explored first. New axially-chiral bis(amide) and bis(urea) proligands are designed. Synthetic methods used to generate these compounds are described and X-ray crystallographic analysis of a bis(sulfonamide) establishes the absolute configuration of the chiral proligands. Installation of the new bis(amidate) and bis(ureate) ligands onto zirconium is undertaken and the structure of these complexes is examined in solution and, where possible, in the solid state. Where well-defined zirconium complexes can be obtained, those complexes are tested for their efficacy in enantioselective catalytic hydroamination. In the absence of well-defined zirconium complexes, an in situ catalyst generation protocol is employed. Catalysts featuring a bis(amidate) ligand derived from 2,2ʹ-diamino-6,6ʹ-dimethylbiphenyl achieve modest hydroamination activity with a primary aminoalkene at 110 °C, with enantiomeric excesses (ee’s) of up to 25%. Catalysts featuring a bis(amidate) ligand derived from 3,3ʹ,5,5ʹ-tetrabromo-2,2ʹ-diamino-6,6ʹ-dimethylbiphenyl display impressive reactivity with a primary aminoalkene, including room temperature hydroamination, with ee’s ranging from 52-55%. Catalysts featuring a bis(ureate) ligand derived from 2,2ʹ-diamino-6,6ʹ-dimethylbiphenyl are shown to be capable of cyclizing secondary aminoalkenes with ee’s up to 63%. Capillary electrophoresis is developed as a method to determine the ee of tertiary amine products. A kinetic study of a catalyst featuring a bis(amidate) ligand derived from 2,2ʹ-diamino-6,6ʹ-dimethylbiphenyl supports established mechanistic proposals for neutral group 4 hydroamination catalysts. Solid state molecular structures, combined with existing knowledge of bonding and catalytic reaction pathways, are used to propose models for how enantioselectivity is achieved through the use of different ligand frameworks.
The use of known ligands in the formation of tantalum complexes for hydroaminoalkylation catalysis is then explored. Installation of such axially-chiral bis(amidate) ligands onto tantalum centres is undertaken and the structure of these complexes is examined in solution and, where possible, in the solid state. Catalytic testing reveals general competence of these catalysts for the hydroaminoalkylation reaction.
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El, Samrout Ola. "Molecules at surfaces : formation, reactivity, assembly of (bio)molecules on external and internal surfaces of nanosized/nanostructured materials." Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS085.
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Cette thèse vise à étudier en profondeur la polymérisation des monomères Gly sur de la silice amorphe afin de mieux comprendre son mécanisme réactionnel, sa cinétique et les paramètres liés à la nature du produit de condensation obtenu dans différentes conditions environnementales. Dans la première partie, le comportement des différents groupes silanol de la silice a été étudié en profondeur par spectroscopie IR pour avoir un aperçu de la réactivité des groupes fonctionnels de la silice. Par la suite, la réaction de formation de liaison peptidique a été largement étudiée sous atmosphère contrôlée avec des mesures de spectroscopie IR in situ pour étudier le comportement des monomères Gly et ceux des groupes fonctionnels de la silice lors de l'adsorption sur la surface ainsi que pendant les étapes intermédiaires de polymérisation. . Un mécanisme d'adsorption/activation des monomères sur la silice suivi de la polymérisation en chaînes linéaires plus longues de poly-Gly a été suggéré. En utilisant la technique MS avec TGA, il a été possible d'évaluer le nombre de mers qui constituent les longs peptides linéaires obtenus sur la surface. De plus, le comportement du poly-Gly au contact de l'eau a également été étudié où les peptides se déplacent pour former des structures auto-assemblées. Dans la seconde partie, la réaction de polymérisation du Gly sur silice amorphe a été étudiée dans des environnements fluctuants : un système soumis uniquement à des fluctuations de température par rapport à un autre soumis à la fois à des fluctuations de température et d'humidité. Les données recueillies par IR in situ ont montré qu'un système soumis à des fluctuations de température et d'humidité représentait le système le plus favorable pour une polymérisation, Par la suite, un mécanisme d'allongement des chaînes linéaires dans des structures ordonnées et auto-assemblées avec des indications de une polymérisation matricielle a été suggérée. La dynamique structurelle des peptides linéaires ainsi que les différentes structures secondaires ont été évaluées au cours de la réaction. De plus, la résistance et la croissance des structures auto-assemblées sur la surface ont été étudiées pendant une durée prolongée de la réaction de polymérisation. Dans la troisième partie, une étude des paramètres qui déterminent la formation de peptides linéaires et de dimères cycliques (DKP) sur la surface de la silice lors du dépôt de Gly à partir des phases gazeuse et liquide a été réalisée. Concernant le dépôt de Gly en phase gazeuse, les monomères ont été déposés par dépôt chimique en phase vapeur sous flux d'argon sur des surfaces de silice de différentes surfaces spécifiques, sous forme vierge ou traitées thermiquement à différentes températures. Les résultats de la spectroscopie IR combinés à ceux de la TGA, de la spectroscopie Raman, de l'ATR, de la XRD et de l'analyse BET ont montré que la présence de types spécifiques de groupes silanol ainsi qu'un cadre renforcé avec de grands anneaux de siloxane favorisent la formation de peptides linéaires sur la silice. surface sur les cycliques. Concernant le dépôt à partir de la phase liquide, différentes charges de Gly ont été déposées sur de la silice de différentes surfaces spécifiques (SSA) en utilisant la méthode d'imprégnation par humidité naissante suivie d'une simple activation thermique. Le SSA de la surface de la silice montre un impact direct sur le type de produit de condensation obtenu et sur la croissance des cristallins en surface. Le rôle bénéfique des molécules d'eau dans la formation de peptides linéaires sur une silice à SSA relativement élevé a également été mis en évidence. Le DKP considéré jusqu'alors comme un produit cyclique sans intérêt a également été étudié sur des surfaces de silice amorphe. Les résultats ont montré que le DKP au lieu d'être un produit sans issue, il représente un dimère utile pour la prolongation rapide des peptides linéairesThis PhD thesis aims to deeply study the polymerization of Gly monomers on amorphous silica to better understand its reaction mechanism, kinetics, and parameters related to the nature of the condensation product obtained under different environmental conditions. In the first part, the behavior of the different silanol groups of silica were deeply studied by IR spectroscopy to have some insights on the reactivity of the silica functional groups. Subsequently, the peptide bond formation reaction was heavily studied under controlled atmosphere with in-situ IR spectroscopy measurements to investigate the behavior of the Gly monomers and the ones of the functional groups of silica upon adsorption on the surface as well during the intermediate steps of polymerization. A mechanism of adsorption/activation of monomers on silica followed by the polymerization into longer linear chains of poly-Gly was suggested. Using MS technique along with TGA, it was possible to evaluate the number of mers that constitute the long linear peptides obtained on the surface. Furthermore, the behavior of the poly-Gly upon contact with water was also studied where peptides move to form self-assembled structures. In the second part, the polymerization reaction of Gly on amorphous silica was studied under fluctuating environments: a system subjected only to temperature fluctuations in comparison with another one subjected to both temperature and humidity fluctuations. The data collected by in-situ IR showed that a system subjected to fluctuations of both temperature and humidity represented the most favor system for a polymerization, Subsequently, a mechanism about the elongation of the linear chains in ordered and self-assembled structures with indications of a templated polymerization was suggested. The structural dynamics of the linear peptides along with the different secondary structures were evaluated during the reaction. Moreover, the resistance and growth of the self-assembled structures on the surface were investigated for an extended duration of the polymerization reaction. In the third part, a study of the parameters that determine the formation of linear peptides and cyclic dimers (DKP) on silica surface upon Gly deposition from gas and liquid phases was carried out. Regarding the Gly deposition from gas phase, the monomers were deposited using chemical vapor deposition under argon flow on silica surfaces of different specific surface areas, in pristine form or thermal treated at different temperatures. The results of IR spectroscopy combined with the ones of TGA, Raman spectroscopy, ATR, XRD, and BET analysis, showed that the presence of specific types of silanol groups along with a framework enhanced with large siloxane rings favor the formation of linear peptides on silica surface over cyclic ones. Concerning the deposition from liquid phase, various Gly loading were deposited on silica of different specific surface areas (SSA) using incipient wetness impregnation method followed by a simple thermal activation. The SSA of silica surface shows a direct impact on the type of the condensation product obtained and on the growth of crystalline on the surface. The beneficial role of water molecules in the formation of linear peptides on a silica with a relatively high SSA was also highlighted. The DKP considered so far as an uninteresting cyclic product was also studied on amorphous silica surfaces. The results showed that DKP instead of being a dead-end product, it represents a useful dimer for the fast prolongation of linear peptides
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Vabre, Roxane. "Fonctionnalisation directe de liaisons C-H et couplages croisés pour la formation de liaisons C-C et C-N : synthèse de purines 6,8,9-trisubstituées." Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-00923198.
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La grande variété de propriétés biologiques associées au noyau purine en fait une structure privilégiée pour la conception et la synthèse de nouvelles molécules à visée thérapeutique. Cette spécificité est étroitement liée à la grande diversité de substituants pouvant être introduits sur les différentes positions du noyau purine et en particulier sur C2, C6, C8 et N9. Par conséquent, le développement de méthodes de fonctionnalisation rapides de cette famille de composés est d'un grand intérêt synthétique. Nous nous sommes focalisés sur la formation de liaisons C-C et C-N sur les positions 6 et 8 du noyau purine pour pouvoir présenter de nouveaux outils de synthèse permettant d'introduire une plus grande diversité fonctionnelle. D'une part, nous avons étudié la fonctionnalisation directe de liaisons C-H de purines, sujet encore peu exploré. En effet, de nos jours, le traditionnel couplage croisé (Negishi, Suzuki-Miyaura), utilisé pour la création de liaisons C-C, se voit de plus en plus concurrencé par ces réactions puisqu'elles ne nécessitent pas la préparation d'un partenaire organométallique. Ce sont des réactions dites à économie d'atomes. En nous basant sur l'expérience du laboratoire dans le domaine de la fonctionnalisation directe de liaisons C-H, nous avons envisagé l'alcénylation et l'alcynylation directes en position 8 de la purine, les motifs alcényle et alcynyle étant présents dans certaines purines d'intérêt biologique. D'autre part, nous nous sommes intéressés à deux méthodes de couplage croisé pallado-catalysé permettant la formation de liaisons C-N et C-C : le couplage de Buchwald - Hartwig entre une 8-iodopurine et des amides ou des amines aromatiques, et le couplage de Liebeskind - Srogl entre une 6-thioétherpurine et divers acides boroniques.
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Prasad, P. K. "Asymmetric synthesis of bioactive molecules and development of synthetic methodologies involving C-C, C-O and C-N bond formation via Cu(I) and iodine catalysis." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2015. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2034.
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Maguire, Frances. "Bonds of print and chains of paper : rethinking print culture and social formation in early modern England, c.1550-c.1700." Thesis, University of York, 2017. http://etheses.whiterose.ac.uk/18920/.
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This thesis examines the employment of print by institutions in early modern England c.1550-c1700, to challenge existing understandings of print culture. Where previous studies of print focus predominantly on the published, public and popular, my research demonstrates that institutions commissioned and distributed print for a variety of communicative and administrative purposes. By engaging critically with the adoption of print, I interrogate the role of documentary culture in the workings of governance. I argue that print increasingly navigated and negotiated a wide set of exchanges and was a critical component in the development and performance of social relations. Examining institutional records and personal papers, this thesis identifies a previously overlooked corpus of print that was implicit to administration and record keeping. My research supplements existing print catalogues to remap the printed landscape of the period. Each section explores a particular institutional setting, looking in turn at the printed output of the Church, the state and London livery companies to reveal the function of print in administrative practice. To do this, it follows the course of printed sheets from printing house to archive. As a result, it charts a very different circulation and consumption of print. This thesis aims to transform ideas of what men and women read, as much as what institutions printed. Scholars have largely ignored this print and the wider ramifications it has for understanding the paperchains that connected institutions and individuals. By taking a material approach to print, this thesis extends the parameters to discuss and study paperwork more broadly. My research contests the association usually drawn between the adoption of print and the emergence of standardisation and bureaucratic efficiency. I argue this has significant implications for conceptions of state formation, social relations and knowledge production in the early modern period.
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Xing, Dong, and 邢栋. "Transition metal-catalyzed C-N bond formation via addition of nitrogennucleophiles towards alkenes and related tandem cyclization reactions." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B46589156.
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Yang, Bin. "Catalytic Stereoselective Formation of C–O, C–C and C–B Bonds : A Voyage from Asymmetric Reactions Enabled by Lipases to Stereoselective Palladium-Catalyzed Oxidative Transformations of Enallenes." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-141519.
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This thesis has been focused on enzymatic kinetic resolutions and stereoselective oxidative transformations of enallenes catalyzed by PdII. In the first part of the thesis, a detailed discussion on Candida antarctica lipase B (CALB)-catalyzed kinetic resolution (KR) of δ-functionalized alkan-2-acetates is shown. We gained a deeper insight into the mechanism of enzyme-substrate recognition. Changing from an anhydrous solvent to water or a water-containing organic solvent enhanced the enantioselectivity. The effect of –OH was also confirmed by a lipase mutant suggesting that the water molecule mentioned above can be partly mimicked. In the second part of the thesis, we developed an efficient KR for allenic alcohols. On this basis, a novel synthesis of optically pure 2-substituted 2,3-dihydrofurans from allenic alcohols via a Ru-catalyzed cycloisomerization was reported. The developed protocol enabled us to assemble an optically pure precursor for total synthesis with three chiral centers from readily available allenol in 2 days. In the third part, we reported a class of reactions involving C–H cleavage under mild conditions: PdII-catalyzed oxidative transformations of enallenes. These reactions are particularly attractive since a number of meticulous structures have been achieved from readily accessible starting materials. The directing effect of an unsaturated hydrocarbon was found to be key for these transformations. In the final part, we developed the carbonylative insertion reaction discussed in the third part of the thesis into an asymmetric version. By using this methodology, a number of cyclopentenone compounds were obtained in good to excellent enantioselectivity.
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Kunchithapatham, Kamala. "Development of Calcium and Palladium Catalysts for the Formation of Carbon-Carbon and Carbon-Heteroatom Bonds." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1337955731.
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Li, Jihui. "Copper-Catalyzed Domino C-N Bond Formation for Synthesis of N-Containing Compounds (Benzimidazoles, Imidazoles, and Guanidines) - Approach toward Total Synthesis of Natural Product Raputindoles." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112130.
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Cette thèse est constituée de trois parties : 1) Le contexte bibliographique, 2) le développement de réactions domino cupro-catalysées et 3) une approche vers la synthèse totale des raputindoles.La première partie introduit d’abord le concept de réactions domino ainsi que leurs applications, puis les réactions catalysées par du cuivre permettant de former des liaisons C-N sont passées en revue en incluant les couplages de Ullmann, Goldberg et de Chan-Lam, les séquences d’activation oxydante de liaisons C-H/formation de liaison C-N, l’insertion de nitrènes et l’hydroamination de liaisons C-C multiples. En se basant sur ces réactions élémentaires permettant de former une liaison C-N unique, les développements récents de réactions domino sont ensuite détaillés.La deuxième partie peut être subdivisée en 3 sections : 1) la synthèse de benzimidazoles, 2) la synthèse d’imidazoles and 3) la synthèse de guanidines. Un rappel des méthodes existantes pour la synthèse de ces motifs est proposé dans chaque section. Notre travail, basé sur la formation de liaisons C-N multiples selon une séquence cupro-catalysée domino, est ensuite détaillé. Celui-ci nous a permis d’aboutir au développement de voies d’accès aux benzimidazoles, en utilisant une réaction séquentielle catalysée par du cuivre en présence d’oxygène à partir d’acides boroniques et d’amidines, à la synthèse d’imidazoles par une réaction de di-amination d’alcynes vrai par des amidines et à l’obtention de guanidines et de 2-aminobenzimidines par une réaction à 3 composant. Ces réactions domino montrent une bonne efficacité et permettent d’assembler des hétérocycles à partir de précurseurs aisément accessibles.La dernière partie est consacrée à la synthèse des raputindoles. La structure, les activités et les réactions clé pour la construction de ces alcaloïdes sont discuté d’abord, nous amenant à proposer une rétrosynthèse pour accéder à ces molécules. Les réactions qui ont retenues notre attention pour construire ces molécules sont une annelation [3+2] irido-catalysée d’acides o-formylarylboronique et de 1,3-diènes, la synthèse de Leimgruber-Batcho pour obtenir des indoles et une séquence d’alkylboration-protodéboration. A partir de cela 3 stratégies ont été évaluées, montrant que l’accès à ce type de composé naturel est envisageable en combinant ces étapesThis thesis consists in three parts: bibliographic background, copper-catalyzed reactions for synthesis of N-containing compounds, approach to the synthesis of raputindoles.The first part introduces the domino reactions and their applications, then, copper-mediated reactions for construction of C-N bond formation are reviewed including Ullmann, Goldberg and Chan-Lam coupling, oxidative C-H activation/C-N formation, insertion of nitrenes and carbenoids, and hydroamination of multi-C-C bonds. This can be used as guides to design domino reaction. Following these copper-mediated single C-N bond formation reactions, recent developments of copper-catalyzed domino reactions for synthesis of heterocycles are described.The second part can be divided into three sections: 1) synthesis of benzimidazoles, 2) synthesis of imidazoles and 3) synthesis of guanidines. Each section summarizes the existing methods used for their synthesis. Following it, our synthetic work involving copper-catalyzed C-N bond formation domino reactions is discussed in detail. Our objectives include the synthesis of benzimidazoles through copper-catalyzed sequential reaction of benzamidines and boronic acids, synthesis of imidazoles via copper-catalyzed domino reaction of benzamidines and acetylenes, and synthesis of guanidines and 2-aminobenzimidazoles by Cu-catalyzed three-component reaction of cyanamides, boronic acids and amines. These copper-catalyzed domino reactions show high efficiencies from readily available and simple starting materials.The last part is about the total synthesis of raputindoles. The structure and bioactivities of raputindoles and key reactions for the total synthesis of raputindoles are introduced first, the synthetic strategies are then proposed on basis of relative synthetic methods. The key reactions we use for the synthesis of raputindoles are iridium catalyzed [3+2] annulation of o-formylarylboronic acids and 1,3-dienes, Leimgruber-Batcho indole synthesis, transition-metal catalyzed SN2 substitution and alkylborylation-protondeborylation. According to the three strategies we proposed, lots of relative reactions were investigated. The results show that it is possible to synthesize the raputindole molecules based on the iridium catalyzed [3+2] annulation of 2-formylarylboronic acids and 1,3-dienes
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Guyonnet, Mathieu. "Synthèse totale d’alcaloïdes de type dibenzopyrrocoline par arylation C(sp3)-H intramoléculaire." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10143.
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La fonctionnalisation de liaisons carbone – hydrogène réputées peu réactives ouvre de nouvelles perspectives en synthèse organique. Une stratégie efficace consiste en l'utilisation de métaux de transition comme le palladium. L'activation C-H organométallique a fait l'objet de nombreux développements méthodologiques au cours des dernières décennies, toutefois peu d'applications de ces travaux en synthèse multi-étapes ou totale sont reportées dans la littérature. Les travaux de recherche décrits dans ce mémoire s'inscrivent dans ce contexte. Nous nous sommes intéressés à la famille des alcaloïdes de type dibenzopyrrocoline, une famille de produits naturels structurellement originaux. Au vu des travaux précédemment reportés dans la littérature, l'analyse rétrosynthétique de ces produits nous a conduits à développer dans un premier temps une séquence N-arylation / bromation / arylation C(sp3)-H intramoléculaire de lactames et analogues qui nous a permis d'accéder à diverses indolines tricycliques fusionnées. Dans un deuxième temps, la synthèse du squelette dibenzopyrrocoline a été entreprise à l'aide de la méthodologie séquentielle développée et la difficulté d'accès au précurseur d'arylation C(sp3)-H intramoléculaire a nécessité l'exploration de différentes voies synthétiques, potentiellement prometteuses. Enfin les différents travaux méthodologiques effectués ont mis à jour la faisabilité de l'arylation C(sp3)-H intramoléculaire d'anilines tertiaires, jamais reportée dans la littératureThe direct functionalization of unactivated C-H bonds represents an atom- and stepeconomical alternative to more traditional synthetic methods based on functional group interconversion. Transition-metal catalysis has recently emerged as a powerful tool to functionalize otherwise unreactive C-H bonds. Whereas a lot of methodological studies have been developed in the past decade, few applications of these methodologies in multi-step or total synthesis have been reported in the literature. In this context, we envisioned the total synthesis of dibenzopyrrocoline alkaloids, a family of structurally original natural products, by using intramolecular C(sp3)-H arylation as a key step. This work led us to first develop a N-arylation / bromination / intramolecular C(sp3)-H arylation sequence which allowed us to access diverse fused tricyclic indolines. We next investigated the application of this strategy to the synthesis of the dibenzopyrrocoline motif. The difficulty to access the C(sp3)-H arylation precursor required an exploration of different synthetic pathways, which proved to be potentially promising. Finally the different performed methodological studies showed the feasibility of the intramolecular C(sp3)-H arylation of tertiary anilines, which was never described in the literature
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Roberts, Deborah Elizabeth. "Palladium N-neterocyclic carbene complexes as catalysts for C-N, C-Si and C-S bond formations." Thesis, University of Sussex, 2013. http://sro.sussex.ac.uk/id/eprint/45342/.
Full textAbstract:
This work is foremost a study of various palladium-bearing N-heterocyclic carbenes complexes and their catalytic potential to form C-N bonds. Both alkyl amination and aryl amination are considered. Further elucidation on the mechanism of such catalytic activity is investigated. The viability of alkyl amination using palladium complexes bearing the ligands, ITMe, 1,2,3,4- tetramethylimidazol-2-ylidene, and ICy, 1,3- bis-cyclohexylimidazol-2-ylidene, as catalysts, is investigated. This includes the synthesis of [Pd(ITMe)(neopentyl)Cl]2,[Pd(ITMe)2(neopentyl)Cl], [Pd(ITMe)(neopentyl)(tbutylamine)Cl], [Pd(ITMe)(neopentyl)(hexylamine)Cl], with successful elimination of the alkyl-amination reaction product in low yield from the latter complex. [Pd(ICy)(neopentyl)Cl]2, [Pd(ICy)2(neopentyl)Cl] are also isolated. Unsuccessful attempts were made to vary the electronic properties of the complexes by replacing the amine with a hydrazine. Work was also done on indirect alkylation using tBuLi which led to a new method for synthesis of [Pd(ItBu)2] and novel complex, [Pd(ItBu)Cl3. ItBuH] (ItBu = 1,3- bis-tertbutylimidazol-2-ylidene). Aryl amination catalysed by complexes of palladium bearing the ligand, ITMe, is considered. This includes an improved synthesis of [Pd(ITMe)2] and synthesis of [Pd(ITMe)2(anisole)Cl]. Unsuccessful attempts at the elucidation of the mechanism of [Pd(ITMe)2(anisole)] formation led to the unexpected formation of [Pd(ITMe)2(SiMe3)(Si(SiMe3)3)] and [Pd(ITMe)2(SiMe3)2]. Aryl amination with using [Pd(ITMe)2(SiMe3)2] led to two aryl amination products, 4-ortho-methoxyphenyl morpholine as well as the expected para isomer. The use of complexes [Pd(ItBu)2] and [Pd(SIPr)2] (SIPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) in C-S bond formation was explored. Addition of mesityl magnesium bromide to Pd(1,5-COD)Cl2 led to addition of mesityl substrate across 1,5-COD double bond and the addition of ITMe formed the Heck cycle intermediate [Pd(8-mesityl-1,4,5-η3 – C8H12)X2] (X=Cl, Br). Addition of 4-tolyl magnesium chloride resulting in the formation of Pd(ItBu)2(tolyl)Cl via an indirect route.
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Aissaoui, Regadia. "Réaction de substitution nucléophile aromatique des acides naphtoïques ortho-fluorés/méthoxylés avec les réactifs de Grignards et les organolithiens (SNArAB)." Phd thesis, Université du Maine, 2012. http://tel.archives-ouvertes.fr/tel-00684960.
Full textAbstract:
Dans ce travail, il est montré que les alkyl/vinyl/aryl lithiens et magnésiens réagissentavec les acides C-1(F/OMe) naphtoïques en l'absence de catalyseur métallique. Cette nouvelleréaction de substitution nucléophile aromatique permet potentiellement de préparer n'importequel biaryle tout en s'affranchissant des étapes de protection et de déprotection de la fonctionacide (CO2H). Les alkyllithiens linéaires et ramifiés réagissent avec la même efficacité que lesalkylmagnésiens même à basse température (-78 °C). Le déplacement d'un fluor ou d'unméthoxy s'effectue avec la même facilité. L'absence d'ortho-lithiation est confirmée par lepiégeage du milieu réactionnel en fin de réaction par l'iodométhane (après addition de n-BuLi,s-BuLi et t-BuLi). Le bromure de vinylmagnésium requiert un chauffage au reflux du THF.La méthode étudiée permet de préparer extrêmement facilement des 1- et 2-phénylnaphtalènes, 1,1'-binaphtalènes et 2,2'-binaphtalènes. Dans les exemples où lesaryllithiens donnent des rendements moyens-faibles en produits de couplage, les réactifs deGrignard sont beaucoup plus efficaces. Le o-tolyllithium, le bromure de o-tolylmagnésium, lebromure de (4-méthoxyphényl)magnésium, le bromure de (2,5-diméthylphényl)magnésium etle bromure de benzo[d][1,3]dioxol-5-ylmagnésium déplacent facilement le groupefluoro/méthoxy en ortho du groupe CO2M pour donner les produits de substitutioncorrespondants alors que la réaction du bromure de (2,6-diméthoxyphényl)magnésium estmoins efficace sans doute en raison de l'encombrement stérique causé par les deux groupesortho-méthoxy. L'acide 1-(2-méthoxyphényl)-2-naphtoïque est un produit particulièrementintéressant. La déprotection du groupe méthoxy suivie d'une cyclisation est réalisée par BBr3pour donner la 6H-naphtho[2,1-c]chromén-6-one qui est isolée avec un rendement de 97 %.Cette lactone est utile pour la préparation de composés atropoisomères optiquement actifsaprès ouverture énantiosélective du cycle lactone selon la technique mise au point parBringmann.
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Ahern, J. M. "Radical hydroacylation of C-C and N-N double bonds in air." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1309819/.
Full textAbstract:
The formation of C-C and C-N bonds in modern organic synthesis is a key target for methodological advancement. Current methods of C-C and C-N bond formation often involve the use of expensive catalysts, or sub-stoichiometric reagents, which can lead to the generation of undesirable waste products. This thesis describes a novel and environmentally benign set of reaction conditions for the formation of C-C and C-N bonds by hydroacylation and this is promoted by mixing two reagents, an aldehyde and an electron-deficient double bond, under freely available atmospheric oxygen at room temperature Chapter 1 will provide an introduction to the thesis and mainly discusses methods for C-C bond formation, in particular, radical chemistry and hydroacylation. Chapter 2 describes the hydroacylation of vinyl sulfonates and vinyl sulfones (C-C double bonds) with aliphatic and aromatic aldehydes with a discussion and evidence for the mechanism of the transformation. Chapter 3 details the synthesis of precursors for intramolecular cyclisations and studies into aerobic intramolecular cyclisations. Chapter 4 describes the hydroacylation of vinyl phosphonates (C-C double bonds) and diazocarboxylates (N-N double bonds) with aliphatic and aromatic aldehydes bearing functional groups. In addition, the hydroacylation of diazocarboxylates with chiral aldehydes will be discussed. In conclusion, a new, facile and clean set of reaction conditions for the formation of C-C and C-N bonds has been developed via aerobic C-H activation of aldehydes providing access to unsymmetrical ketones.