Дисертації з теми "C-C bonds"
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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.
Повний текст джерелаCette 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.
Rix, Kathryn. "Electrochemical reduction of amides and c=c bonds." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/39846.
Повний текст джерелаKanuru, Vijaykumar. "Understanding surface mediated C-C and C-N bond forming reactions." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608956.
Повний текст джерелаBowen, 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.
Повний текст джерелаLee, Kang-sang. "New Concepts and Catalysts for Enantioselective Synthesis of C-C, C-Si, and C-B Bonds." Thesis, Boston College, 2010. http://hdl.handle.net/2345/1739.
Повний текст джерелаChapter 1. The development of chiral monodentate N-heterocyclic carbenes (NHCs) is presented. Structurally varied twenty-eight new chiral imidazolinim salts, NHC precursors, were synthesized and characterized. Chapter 2. The first example of Cu-catalyzed enantioselective conjugate additions of alkyl- and arylzinc reagents to unactivated cyclic enones is presented. Transformations are promoted in the presence of 2.5-15 mol % of a readily available chiral NHC-based Cu complex, affording the desired products bearing all-carbon quaternary stereogenic centers in 67-98% yield and in up to 97% ee. Catalytic enantioselective reactions can be carried out on a benchtop, with undistilled solvent and commercially available (not further purified) Cu salts. Chapter 3. A new class of enantioselective conjugate addition (ECA) reactions that involve aryl- or alkenylsilylfluoride reagents and are catalyzed by chiral non-C2-symmetric Cu-based NHC complexes are presented. Transformations have been designed based on the principle that a catalytically active chiral NHC-Cu-aryl or NHC-Cu-alkenyl complex can be accessed from reaction of a Cu-halide precursor with in situ-generated aryl- or alkenyl-tetrafluorosilicate. Reactions proceed in the presence of 1.5 equivalents of the aryl- or alkenylsilane reagents and 1.5 equivalents of tris(dimethylamino)sulfonium difluorotrimethylsilicate. Desired products are isolated in 63-97% yield and 73.5:26.5-98.5:1.5 enantiomeric ratio (47%-97% ee). Chapter 4. An efficient Cu-catalyzed protocol for enantioselective addition of a dimethylphenylsilanyl group to a wide range of cyclic and acyclic unsaturated ketones, esters, acrylonitriles and dienones is presented. Reactions are performed in the presence of 1-5 mol % of commercially available and inexpensive CuCl, a readily accessible monodentate imidazolinium salt as well as commercially available (dimethylphenylsilyl)pinacolatoboron. Cu-catalyzed 1,4- and 1,6-conjugate additions afford the enantiomerically enriched silanes in 72%-98% yield and 90:10->99:1 enantiomeric ratio (er) with up to >25:1 of Z:E selectivity. Chapter 5. A Cu-catalyzed method for enantioselective boronate conjugate additions to trisubstituted alkenes of acyclic a,b-unsaturated carboxylic esters, ketones, and thioesters is presented. All transformations are promoted by 5 mol % of a chiral monodentate NHC-Cu complex, derived from a readily available C1-symmetric imidazolinium salt, and in the presence of commercially available bis(pinacolato)diboron. Reactions are efficient (typically, 60% to >98% yield after purification) and deliver the desired boryl carbonyls in up to >98:2 enantiomer ratio (er). In addition, metal-free, nucleophilic activation of a B-B bond has been exploited in the development of a highly efficient method for conjugate additions of commercially available bis(pinacolato)diboron to cyclic or acyclic a,b-unsaturated carbonyls. Reactions are readily catalyzed by 2.5-10 mol % of a simple NHC. A variety of cyclic and acyclic unsaturated ketones and esters can serve as substrates. Transformations deliver boryl carbonyls bearing tertiary as well as quaternary B-substituted carbons in up to >98% yield
Thesis (PhD) — Boston College, 2010
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
Owen, Gareth Richard. "Palladium-mediated transformationand activation of unsaturated C-N, C-S and C-O bonds." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408281.
Повний текст джерелаJiang, 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.
Повний текст джерелаAt the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.
Ziadi, Asraa. "Metal-catalyzed functionalization of c-c bonds in four-membered rings." Doctoral thesis, Universitat Rovira i Virgili, 2014. http://hdl.handle.net/10803/320185.
Повний текст джерелаRecientemente la funcionalización catalítica de enlaces C-C ha suscitado un gran interés en la comunidad científica a pesar de los retos que conlleva. Esta tesis doctoral se ha basado en diseñar nuevos procesos catalíticos para la funcionalización de enlaces C-C en anillos de cuatro miembros. Específicamente, se ha demostrado la viabilidad de preparar cetonas con grupos arilo en posición γ usando precatalizadores de Pd para promover la rotura de enlaces C-C en anillos de tert-ciclobutanol utilizando cloruros de arilo y tosilatos como agentes arilantes (Capítulo 2). La transformación se caracteriza por su amplia generalidad y baja carga de catalizador. La selectividad de la reacción puede ser fácilmente controlada por la naturaleza del ligando, en la que fosfinas con grupos ricos en electrones y voluminosos dan los mejores resultados, evitando la β-eliminación de hidrógeno de las especies organometálicas intermedias. Considerando los precedentes del Capítulo 2, se ha extendido esta metodología al acoplamiento con haloacetilenos para preparar cetonas con grupos alquino en posición γ (Capítulo 3). Curiosamente, los substituyentes del grupo alquino juegan un papel fundamental en la reactividad, pudiéndose controlar mediante la utilización de un cierto ligando. En el Capítulo 4, se ha desarrollado una nueva transformación basada en una reacción catalizada por compuestos de Ni para efectuar la síntesis de anillos de ocho eslabones mediante una reacción formal de cicloadición [4+4] de benzociclobutanonas y dienos simples. Curiosamente, dicho método muestra una especial preferencia para formar anillos de ocho eslabones sobre los, a priori, anillos de 6 eslabones que son más estables termodinámicamente. En la presente tesis doctoral se ha estudiado también la viabilidad de llevar a cabo una fijación catalítica de CO2 y la formación de enlaces C-F mediante una rotura de enlaces C-C (Capítulo 5) aunque no se han encontrado las condiciones óptimas para llevar a cabo tales transformaciones.
The means to promote catalytic C-C bond-functionalization has gained a considerable attention in recent years and probably can be considered one of the most challenging and vibrant subjects in organometallic chemistry. This PhD thesis deals with the design of new metal-catalyzed functionalization of C-C bonds in four-membered ring frameworks. Specifically, we have demonstrated the viability of preparing γ-arylated ketones via Pd-catalyzed cleavage of C-C bonds in tert-cyclobutanol using aryl chloride or tosylate counterparts (Chapter 2). The transformation possesses a wide substrate scope and remarkable low catalyst loadings. Selectivity was controlled by the ligand in which electron-rich and sterically-hindered phosphine ligands provided a unique reaction outcome that avoided the proclivity of alkyl metal species towards destructive β−hydride elimination. Prompted by the precedents in Chapter 2, we successfully extended the scope of the metal-catalyzed C-C bond-cleavage of tert-cyclobutanols by using halo acetylene counterparts giving γ-alkynylated ketones (Chapter 3). Interestingly, substituents on the alkyne motif showed a remarkable influence on reactivity. Of particular interest is the application profile of such methodology since γ-alkynylated ketones could promote consecutive metal-catalyzed transformations into valuable synthetic intermediates. In Chapter 4, we extended the interest for C-C bond-cleavage beyond the use of tert-cycñobutanols. Specifically, we developed a Ni-catalyzed C-C bond-cleavage event in benzocyclobutenones for preparing eight-membered rings via formal [4+4]-cycloaddition with dienes (Chapter 4). The method shows a specific preference for eight-membered rings over thermodynamically more stable six-membered rings. This PhD thesis has also studied the development of catalytic CO2 fixation and C-F bond-formation via C-C bond-cleavage (Chapter 5). While we have not found reaction conditions to effect the desired transformations, our research group is actively involved in related catalytic endeavors and it is expected that such research will shed light into the targeted CO2 fixation or C-F bond-forming reactions via C-C bond-cleavage.
Sau, Roca Míriam. "From Click Chemistry to catalytic cleavage of unstrained C-C bonds." Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/396080.
Повний текст джерелаÉsta tesis doctoral está basada principalmente en la síntesis de moléculas pequeñas potencialmente útiles para investigaciones avanzadas. Se han empleado diferentes metodologías para obtenerlas: 1) Cicloadiciones intramoleculares entre un alkino y una azida libres de cobre para la obtención de derivados de benzodiazepinas. Se han obtenido una gran variedad de triazoles fusionados a heterociclos de siete miembros. Posteriormente se han realizado pruebas de actividad biológica de las moléculas resultantes. 2) a) Escisión de enlaces carbono-carbono no activados de amino alcoholes y utilitzación de éstos como nucleófilos conjuntamente con bromuros de arilo para una reacción de acoplamiento catalizada por paladio para la obtención de derivados de dibenzil aminas. Se ha realizado una gran optimización de las condiciones de reacción; base, disolvente, electrófilo, temperatura, catalizador y ligando. b) Escisión de enlaces carbono-carbono no activados de N-alilo amino alcoholes y la utilización de éste como nucleófilo conjuntamente con bromuros de arilo en una reacción de acoplamiento catalizada por paladio para la obtención de aldehídos arilados en posición beta. Se ha realizado la síntesis de un gran numero de amino alcoholes nuevos y éstos se han sometido a las condiciones optimizadas de reacción. Demostrando que ésta transformación es útil para una gran variedad de sustratos (bromuros de arilo y amino alcoholes). La enamina resultante de la reacción de acoplamiento se ha alquilado con vinil metil cetona con buenos rendimientos pero pobres diastereoselectividades aunque se ha demostrado que la reacción es factible. Para finalizar, se ha desarrollado la versión enantioselectiva de la anterior transformación obteniendo buenos excesos enantioméricos aunque con bajos rendimientos.
This PhD thesis is based basically on synthesis of small molecules potentially useful for further investigations. Different strategies have been used to obtain them; 1) Copper free intramolecular cycloadditions between an azide and an akyne for the obtention of benzodiazepine derivatives. A wide range of triazoles fused to seven membered heterocycles rings have been obtained. Later, biological studies have been carried out. 2)a) Carbon-carbon bond cleavage of amino alcohols has been carried out with the subsequent use of them as a nucleophile together with aryl bromides to develop a cross-coupling reaction for the obtention of dibenzyl amines. A wide optimization of the reaction parameters was carried out; base, ligand, catalyst, electrophile, temperatura, and solent. b) Carbon-carbon bond cleavage of N- allyl amino alcohols has been carried out with the subsequent use of them as a nucleophile together with aryl bromides to develop a cross-coupling reaction for the obtention of beta arylated aldehydes. An important number of new amino alcohols have been synthesized and these have been subjected to the optimized reaction conditions. It has been demonstrated that this transformation is useful for a wide range of substrates (amino alcohols and aryl bromides). The resultant enamine has been alkylated with methyl vinyl ketone with good yields but poor diastereoselectivity. To finish the enantioselective version of beta functionalization of aldehydes has been developed obtaining good enantioselectivity but poor yields
Chudasama, V. "The use of aerobic aldehyde C-H activation for the construction of C-C and C-N bonds." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1324525/.
Повний текст джерелаZhao, 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.
Повний текст джерелаAt the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 1: Accepted.
Song, Weifeng. "Cobalt- and Nickel-Catalyzed Functionalization of Unactivated C–Hal, C–O and C–H Bonds." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://hdl.handle.net/11858/00-1735-0000-0001-BC70-0.
Повний текст джерелаRadomkit, Suttipol. "New Concepts, Catalysts, and Methods for Enantioselective Synthesis of C-B and C-C Bonds." Thesis, Boston College, 2016. http://hdl.handle.net/2345/bc-ir:107272.
Повний текст джерелаChapter 1. Part A: N-Heterocyclic Carbenes Catalyzed Enantioselective Boryl Conjugate Additions to α,β-Unsaturated Ketones, Esters, Weinreb Amides and Aldehydes. The first broadly applicable enantioselective boryl conjugate addition reactions to a variety of α,β-unsaturated carbonyls are reported. Transformations are promoted by 5.0 mol % of a chiral Lewis basic N-heterocyclic carbene. The distinctive feature of the reactions in chemoselectivity of the method compared to the Cu-catalyzed variants has been illustrated. Part B: Enantioselective Synthesis of Boron-Substituted Quaternary Carbon Stereogenic Centers through N-Heterocyclic Carbenes Catalyzed Boryl Conjugate Additions to Cyclic and Acyclic Enones The first examples of Lewis base catalyzed enantioselective boryl conjugate additions that afford products containing boron-substituted quaternary carbon stereogenic centers are presented. The carbon–boron bond forming reactions are promoted by 1.0–5.0 mol % of a chiral N–hererocyclic carbene. Cyclic or linear α,β–unsaturated ketones can be used as suitable substrates and the desired products are obtained in 63–95% yield and 91:9 to >99:1 enantiomeric ratio. The utility of the Lewis base-catalyzed approach is demonstrated in the context of an enantioselective formal synthesis of antifungal natural product crassinervic acid. Chapter 2. Enantioselectivity Fluctuations in Phosphine–Cu-Catalyzed Enantioselective Boron-Allyl Addition to Aryl-Substituted Olefins. Catalytic enantioselective multicomponent processes involving B2(pin)2, aryl or heteroaryl monosubstituted olefins, and allylic phosphates or carbonates are disclosed. Transformations promoted by a chiral Cu–phosphine complex afford products that contain a primary C–B(pin) bond and an allyl-substituted tertiary carbon stereogenic center in up to 84% yield and 98:2 enantiomeric ratio. The utility of the approach is showcased in the enantioselective formal synthesis of biologically active heliespirones A and C. Based on mechanistic and computational studies, we show that enantioselectivities variations can depend on electronic and/or steric factors of the alkene substrate and the allyl electrophile as well as their concentration. In most cases, selectivity loss can be minimized and that the resulting insights are also applicable to reactions involving Cu–H species. Chapter 3. Synthesis of Vicinal Diboronate Compounds through Practical Phosphine–Copper Catalyzed Three-Component Processes. The phosphine–Cu-catalyzed multicomponent processes have been developed for a practical and direct synthesis of vicinal diboronate compounds. Reactions of alkenyl–boronates, allylic phosphates, and diboron reagents are promoted by 2.5–10 mol % of a Cy3P–Cu complex affording a wide range of desirable vicinal diboronate products. The ability for easy access to either regioisomers of the products with a C–B(pin) and an adjacent C–B(dan) bond that can be site-selectively functionalized is a noteworthy feature of the method
Thesis (PhD) — Boston College, 2016
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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.
Повний текст джерелаCatalytic 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
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.
Повний текст джерелаAt the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 6: Manuscript.
Page, Michael John Chemistry Faculty of Science UNSW. "Activation of unsaturated NΞN, C=O, and C=C bonds using complexes of ruthenium and rhodium". Publisher:University of New South Wales. Chemistry, 2008. http://handle.unsw.edu.au/1959.4/43366.
Повний текст джерелаAhern, 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/.
Повний текст джерелаPardue, Daniel B. "Computational Studies of C–H/C–C Manipulation Utilizing Transition Metal Complexes." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc801892/.
Повний текст джерелаMkhalid, Ibraheem Ahmed I. "Transition metal catalysed borylation of C-H bonds." Thesis, Durham University, 2006. http://etheses.dur.ac.uk/2694/.
Повний текст джерелаBencivenga, Nicholas Ernest. "Enantioselective nickel catalysis : exploiting activated C-H bonds." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/73437.
Повний текст джерелаCataloged from PDF version of thesis.
Includes bibliographical references (p. 26-27).
A method for the nickel-catalyzed cross-coupling between benzoxazole and secondary halides was explored. This method was to make use of the activated C-H bond found in benzoxazole at the 2-position to generate the nucleophilic species in situ. After an extensive survey of parameters no such method could be found. However, it was found that copper(I) salts promoted the coupling of benzoxazole and benzylic bromides in high yield, albeit in a racemic fashion. Additionally a method to cross-couple terminal alkynes with secondary halides employing nickel-catalysis was explored. After surveying a number of alkynylmetal species, generated in situ, alkynyl borates were found to cross-couple with allylic chlorides to furnish product with the best enantioselectivity (enantiomeric excess ca. 70%), however in low yield.
by Nicholas Ernest Bencivenga.
S.M.
Wang, Anqi. "Cu-Catalyzed Amination of sp3 C-H Bonds." Digital WPI, 2018. https://digitalcommons.wpi.edu/etd-dissertations/509.
Повний текст джерелаCettolin, M. "IRON AND RUTHENIUM CATALYSTS FOR THE REDUCTION OF C=O AND C=N BONDS." Doctoral thesis, Università degli Studi di Milano, 2018. http://hdl.handle.net/2434/543550.
Повний текст джерелаGooseman, Natalie. "The influence of the C-N⁺------F-C charge dipole interaction in fluoro organic chemistry /." St Andrews, 2008. http://hdl.handle.net/10023/695.
Повний текст джерелаYahaya, N. P. "Cyclometallation at Pd, Mn and Co : functionalisation of C-H and C≡C bonds involving cyclisation, rearrangement and isomerisation processes." Thesis, University of York, 2016. http://etheses.whiterose.ac.uk/12566/.
Повний текст джерелаDryzhakov, Marian. "Nitro-assisted Brønsted acid catalysis : activation of C(sp3)–O and C(sp3)–F bonds." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAF012/document.
Повний текст джерелаAlcohols are attractive electrophilic partners for nucleophilic substitution reactions as water is the only by-product in a reaction with protic nucleophiles. Despite being a highly desirable reaction, the scope of useful catalytic transformations remains limited to specific alcohol-nucleophile pairs and a general set of catalytic conditions remains elusive. This thesis describes the development of a general and mild catalyst system for the activation of a broad range of π-activated and aliphatic alcohols to address key limitations in the field. B(C6F6)3•H2O, a strong Brønsted acid, when combined with nitromethane has been found as a widely useful catalyst system for chemoselective alcohol substitution in the presence of acid sensitive functionalities and protecting groups without the typical compromises in reaction rates, substrate/nucleophile scope and catalyst loading. In particular, a co-catalytic effect of nitro compounds is described for the B(C6F6)3•H2O catalyzed azidation of tertiary aliphatic alcohols, enabling catalyst turnover for the first time. On the basis of kinetic, electronic, and spectroscopic investigations, higher order hydrogen-bonded aggregates of nitro compounds and acids are proposed as kinetically competent Brønsted acid catalysts at the origin of the enhanced reactivity. The utility of the new catalytic conditions has been extended beyond alcohol activation and applied to the cleavage of strong C–F bonds in defluorinative Friedel-Crafts reactions of tertiary aliphatic fluorides
Horiuti, Toshihide. "Studies on Enantioselective Addition to C=C Bonds Catalyzed by Transition Metal-Phosphine-Phosphite Complexes." Kyoto University, 1997. http://hdl.handle.net/2433/202317.
Повний текст джерелаBeagley, Paul. "Ansa-titanocenes for enantioselective reduction of C=X bonds." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.557602.
Повний текст джерелаDa, Cruz Ana Cristina Fernandes. "C-H bonds as functional groups for palladium catalysis." Thesis, University of Bath, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.586169.
Повний текст джерелаStenhagen, Ida Sofia Refsholt. "New methods for the construction of C-18F bonds." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:871a7e8c-a4d3-4acb-a25d-5946dec2f44d.
Повний текст джерелаGómez, Palomino Alejandro. "Titanium(IV) enolate chemistry applied to the stereoselective construction of C–C and C–O bonds. New ionic and radical processes." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/665122.
Повний текст джерелаEn la presente Tesis continuamos un estudio previo sobre el carácter nucleófilo de los enolatos de titanio(IV) en adiciones de Michael con control por sustrato. Así, la adición de Michael de (S)-2-benciloxi-3-pentanona a enonas y nitroalquenos se evaluó a fondo en el Capítulo 1. En el caso de las vinil cetonas, las mejores condiciones de reacción implicaban el uso de dos equivalentes de TiCl4 o un equivalente de TiCl4 y otro de SnCl4 y proporcionaban los aductos 2,4-anti-4,5-anti con rendimientos excelentes y diastereoselectividades superiores a 90:10. Además, la metodología desarrollada también se empleó con nitroalquenos α,β-insaturados, conduciendo a proporcionar los aductos de 2,4-anti-4,5-syn con buenas diastereoselectividades y rendimientos. En el Capítulo 2 se reevaluó la retrosíntesis inicial del anillo tetrahidropiránico del fragmento C1-C9 del herboxidieno/GEX1A. La síntesis estereoselectiva del anillo de tetrahidropirano se logró con éxito siguiendo dos enfoques diferentes. En el primer enfoque, se aumentó el número de pasos, pero la secuencia siguió una ruta completamente estereoselectiva aprovechando la gran selectividad ofrecida por una dimetilpirrolamida en condiciones ácidas. En el segundo enfoque, se siguió la secuencia original, pero la supresión de operaciones de purificación innecesarias y la inclusión de una etapa de isomerización final aumentaron notablemente el rendimiento. El segundo objetivo de esta Tesis fue examinar la reactividad radical poco común de enolatos de titanio derivados de N-acil oxazolidinonas quirales cuando se exponen a reactivos radicalarios. Así, en el Capítulo 3, la aminoxilación de N-acil oxazolidinonas quirales se mejoró usando una tiazolidintiona de tert-butilo quiral derivada de tert-leucina que proporcionó los productos aminoxilados como únicos diastereómeros con rendimientos excelentes. Además, en el Capítulo 3 también llevamos a cabo una hidroxilación directa altamente estereoselectiva de enolatos de titanio a partir de N-acil oxazolidinonas quirales con oxígeno para la síntesis de derivados α-hidroxicarboxílicos enantioméricamente puros. En el Capítulo 4 describimos una búsqueda exhaustiva de compuestos capaces de participar en reacciones radicales, lo que implicó una breve exploración de la catálisis fotoredox. Finalmente, tal investigación llevó al descubrimiento de una nueva alquilación altamente estereoselectiva con peróxidos de diacilo alifáticos que conducía a la formación de los aductos alquilados como diastereómeros únicos con rendimientos excelentes.
Harkness, Gavin J. "Sequential processes using catalytic C-O bond activation." Thesis, University of St Andrews, 2018. http://hdl.handle.net/10023/12809.
Повний текст джерелаVinogradova, Ekaterina V. (Ekaterina Viktorovna). "Development of new catalytic transformations and reagents for the construction of C-N and C-S bonds." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/97987.
Повний текст джерелаCataloged from PDF version of thesis. Vita.
Includes bibliographical references.
Chapter 1. Palladium-Catalyzed Cross-Coupling of Aryl Chlorides and Triflates with Sodium Cyanate: A Practical Synthesis of Unsymmetrical Ureas. An efficient method for palladium-catalyzed cross-coupling of aryl chlorides and triflates with sodium cyanate is reported. The protocol allows for the synthesis of unsymmetrical N,N'-di- and N,N,N'-trisubstituted ureas in one pot, and is tolerant of a wide range of functional groups. Insight into the mechanism of aryl isocyanate formation is gleaned through studies of the transmetallation and reductive elimination steps of the reaction, including the first demonstration of reductive elimination from an arylpalladium isocyanate complex to produce an aryl isocyanate. Chapter 2. Palladium-Catalyzed Synthesis of N-Aryl Carbamates. An efficient synthesis of aryl carbamates was achieved by performing palladiumcatalyzed cross-coupling of ArX (X = CI, OTf) with sodium cyanate in the presence of alcohols. The use of aryl triflates as electrophilic components in this transformation allowed for an expanded substrate scope for the direct synthesis of aryl isocyanates. This methodology provides direct access to major carbamate protecting groups, Sthiocarbamates, and diisocyanates, which are precursors to polyurethane materials. Chapter 3. Structural Reevaluation of the Electrophilic Hypervalent Iodine Reagent for Trifluoromethylthiolation. Hypervalent iodine [lambda]3-benziodoxoles are common electrophilic transfer reagents known for their enhanced stability compared to their non-cyclic analogues. Here we present data showing that chlorobenziodoxole reacts with two different thiolate nucleophiles (thiocyanate and trifluoromethylthiolate) resulting in the formation of stable thioperoxy complexes rather than the expected benziodoxole derivatives. We further report a revised structure for the earlier described electrophilic trifluoromethylthiolation reagent (1), previously believed to contain the benziodoxole framework. Our findings, which are based on a combination of analytical techniques, including the recently introduced crystalline sponge method for X-ray analysis, unambiguously demonstrate that 1 is a thioperoxy compound both in solution and the solid state. Chapter 4. Organometallic Palladium Reagents for Cysteine Bioconjugation. Organometallic palladium reagents for the selective S-arylation of biomolecules are described. This new bioconjugation toolkit provides a highly versatile technique for the fast functionalization of cysteine with aromatic scaffolds under a broad range of reaction conditions (e.g., pH, solvent, temperature). The resulting bioconjugates are stable under basic and acidic conditions, as well as in the presence of external thiol nucleophiles. The substitution pattern on the aryl ring can be varied to achieve high levels of stability toward oxidation. Lastly, new types of bio-therapeutics - stapled peptides and linker-free antibody-drug conjugates - could be synthesized using the new method.
by Ekaterina V. Vinogradova.
Ph. D. in Organic Chemistry
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.
Повний текст джерелаFormation 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
Hough, Sarita Elizabeth. "Regioselective, Nucleophilic Activation of C-F Bonds in o-Fluoroanilines." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90657.
Повний текст джерелаMaster of Science
This thesis describes reactions of fluorinated anilines with titanium amides to make fluorinated 1,2-phenylenediamines. The reaction gives high to moderate yields, and is highly selective for ortho substitution. The scope of the reaction, trends in reactivity among substrates, product characterization, and reaction mechanism are discussed. This reaction is of interest because fluorinated aniline derivatives are a privileged structural motif in pharmaceuticals and agricultural chemicals. The first chapter presents an overview of C-F bond activation and key background information. Chapter 2 is a description of the experiments and an in-depth analysis of their results. Chapter 3 presents detailed characterization data for substances generated in this research. Chapter 4 comprises some concluding remarks and plans for possible future extensions of the research.
Smith, Jennifer. "Novel iridicycles for the asymmetric reduction of C=N bonds." Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2049619/.
Повний текст джерелаYang, 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.
Повний текст джерелаWang, Jiaqi. "Transition Metal Catalyzed Oxidative Cleavage of C-O Bond." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc801914/.
Повний текст джерелаZhang, Yuyang. "Functionalization of alpha- and beta-Amino C-H Bonds Using Cooperative Catalysis:." Thesis, Boston College, 2020. http://hdl.handle.net/2345/bc-ir:108932.
Повний текст джерелаCooperative catalysis has been developed for transformations where at least two reactants are activated in situ by acid or base sensitive catalysts to form the reactive species and subsequent bond formation leads to desired product. This thesis focuses on the development of ɑ-amino C-H alkynylation and β-amino C-H deuteration through the use of cooperative catalysts. In the alkynylation reaction, N-alkylamines and trimethylsilyl substituted alkynes were used to synthesize propargylamines by the cooperative actions of Lewis acid catalysts, B(C₆F₅)₃ and copper complex. The reaction between in situ generated iminium ion and copper alkyne complex afforded the product. The method is applicable to the late-stage functionalization of bioactive amine drug molecules and has been shown to tolerate different functional groups on trimethylsilyl-substituted alkynes. In addition, an enantioselective and diastereoselective version of the method was also developed through the use of chiral copper complex. In the second part, selective deuteration of β-amino C-H bonds of various acylic and cyclic alkyl amines will be introduced. B(C₆F₅)₃ and Brønsted base work cooperatively to afford enamine and deuterated ammonium ion as reactive intermediate. Deuteration of enamine at the β-position and hydride reduction at the ɑ-position gave the selectively deuterated products. Acetone-d₆ was the found to be the optimal source of deuterium. This method was able to incorporate deuterium atoms up to 99% and can be applied in a gram scale reaction without compromising the yield or d-incorporation level
Thesis (MS) — Boston College, 2020
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
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.
Повний текст джерелаCHIODI, DEBORA. "Oxo-rhenium-catalyzed Biomimetic Cyclizations and Late-stage Electrochemical C–H Oxidation of Unactivated C(sp3)–H Bonds." Doctoral thesis, Università degli studi di Pavia, 2022. http://hdl.handle.net/11571/1450084.
Повний текст джерелаPart A: Oxo-rhenium-catalyzed Biomimetic Cyclization Biomimetic cyclizations are remarkable tools because a significant increase in molecular complexity can be obtained in a single step. In the first part of my PhD, a new method to promote biomimetic cyclizations of terpenoid-like starting materials using an oxo-rhenium complex as a catalyst is described. This proof of concept, if further explored, will give access to useful building blocks that can be employed for the total synthesis of natural products. Part B: Electrochemical C–H Oxidation The site-specific oxidation of “strong”, non-acidic C(sp3)–H bonds is a rewarding, yet difficult topic in organic synthesis. In the second part of my PhD, N-ammonium ylides are described as tunable, electrochemically driven oxidants for site-specific, chemoselective C(sp3)–H oxidation. This ylide-based approach to C–H oxidation exhibits a unique selectivity relative to other classes of chemical oxidants and can be applied to real-world problems.
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.
Повний текст джерелаThis 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
Yang, Jian Brookhart Maurice S. "Iridium-catalyzed reduction of C-X bonds X = F, Cl, Br, I, O bonds with triethylsilane." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,2639.
Повний текст джерелаTitle from electronic title page (viewed Oct. 5, 2009). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry." Discipline: Chemistry; Department/School: Chemistry.
Williams, Glynn. "The ruthenium catalysed catalysed asymmetric transfer hygrogenation of C=N bonds." Thesis, University of Warwick, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425545.
Повний текст джерелаArockiam, Percia Beatrice. "Ruthenium (II) catalyzed functionalization of C-H bonds : catalysis in water." Rennes 1, 2012. http://www.theses.fr/2012REN1S171.
Повний текст джерелаIn this doctoral thesis, we have shown that Ru(CO₂R)₂(p-cymene) catalyst the insitu generated from [RuCl₂(p-cymene)]₂ and KCO₂R, acts as an excellent catalyst for ortho C-H bond functionalization of arenes containing an heterocycle (pyridine, oxazoline, pyrazole) with unactivated aryl chlorides in the presence of K₂CO₃ as a base. The reactions were performed in diethyl carbonate (DEC) or in water as a solvent instead of N-methylpyrrolidone (NMP), the solvent of choice used in most of ruthenium catalyzed C-H bond transformations. The activity of these catalysts is higher in water than in other organic solvents. We have also disclosed a new catalytic system based on [RuH(codyl)₂]BF₄/2KY(KY: KOAc, KOPiv, KPI) in which the ligand Y promotes the initial cleavage of C-H bonds and the efficiency of this catalytic system depends also on the nature of both substrates involved in the reaction. The directed dehydrogenative alkenylation of N-aryl pyrazoles by styrene and alkyl acrylates catalyzed by Ru(OAc)₂(p-cymene) in the presence of a catalytic or stoichiometric amount of Cu(OAc)₂ H₂O in air is also presented and it is demonstrated that the acetic acid solvent plays a key role. A new method to generate the oxidative homocoupling of N-phenylpyrazole is shown with the Ru(OAc)₂(p-cymene) catalyst
Buscemi, Gabriella. "Functionalisation of aromatic C-H bonds with dicarbene transition metal catalysts." Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3426071.
Повний текст джерелаIl presente progetto di ricerca riguarda l’applicazione di complessi dicarbenici di metalli di transizione in reazioni di funzionalizzazione/attivazione di legami C-H aromatici. L’efficienza catalitica di questi complessi è stata principalmente valutata nella reazione di idroarilazione di alchini (reazione di Fujiwara), che consiste nell’addizione di areni ad alchini interni o terminali catalizzata da semplici composti di palladio(II), come Pd(OAc)2. Questa reazione decorre in ambiente acido, generalmente acido trifluoroacetico, a temperatura ambiente e presenta una elevata ed inusuale regio- e stereoselettività: si ottengono infatti come prodotti principali i cis-arilalcheni, che sono le olefine termodinamicamente meno favorite. La reazione appare molto promettente dal punto di vista tecnologico, anche perché sono conosciute sia la versione inter- che quella intramolecolare, permettendo quindi la funzionalizzazione di eterocicli aromatici e la sintesi di cumarine. La potenziale applicazione industriale richiede però l'ottimizzazione delle condizioni di reazione, poichè la reazione è spesso lenta, necessita di un eccesso di arene rispetto all’alchino e viene condotta con un elevato tenore di catalizzatore (1-5%), fattore che incide pesantemente sul costo del processo. Altri centri metallici, come Pt(II), Au(I) e Au(III), sono stati impiegati come catalizzatori alternativi, ma la loro reattività sembra essere inferiore a quella mostrata dai composti di palladio(II). Sono stati utilizzati anche centri metallici elettrofilici non nobili, ma la loro reattività è inferiore e/o la loro applicabilità limitata ai soli aril-acetileni. L’obiettivo iniziale di questo progetto di tesi è stato quindi quello di migliorare le rese della reazione e diminuire il tenore di catalizzatore. Leganti carbenici N-eterociclici possono aumentare la stabilità del catalizzatore nelle condizioni di reazione e quindi la sua reattività. I complessi monocarbenici di palladio(II), (IPr)Pd(OAc)2 e (IPr)Pd(OOCCF3)2 (IPr = N,N’-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene) sono infatti gli unici complessi ad essere risultati attivi nella reazione di Fujiwara senza bisogno di promotori, sebbene la loro reattività sia comparabile a quella mostrata da Pd(OAc)2. Nella prima parte di questo lavoro di ricerca è stato dimostrato che complessi dicarbenici di palladio(II) catalizzano la reazione ad 80 °C, con eccellenti conversioni e selettività a basso tenore di catalizzatore (0.1%) e con i reagenti in rapporto equimolare. Questi complessi hanno mostrato una reattività maggiore rispetto al semplice palladio acetato ed al complesso monocarbenico (12) testati nelle stesse condizioni di reazione. Sono stati impiegati in questo studio anche complessi dicarbenici di Pt(II), che si sono dimostrati più attivi dei sistemi catalitici di platino riportati in letteratura. Il protocollo ottimizzato è risultato abbastanza generale per quanto riguarda gli alchini, mentre la sua applicabilità agli areni è al momento limitata a molecole elettron-ricche. Questa è comunque una limitazione di tutti i sistemi catalitici di Pd e Pt riportati in letteratura per l’idroarilazione di alchini. Una seconda parte del lavoro ha riguardato l’identificazione della specie cataliticamente attiva. Studi meccanicistici condotti ad 80 °C, variando sia il legante dicarbenico che i leganti anionici al metallo, hanno mostrato che la specie cataliticamente attiva mantiene il legante dicarbenico nella sua sfera di coordinazione, mentre i leganti anionici vengono rimossi dal complesso attraverso uno scambio con l’anione trifluoroacetato derivante dal solvente acido. L’efficienza catalitica del complesso non dipende dal tipo di leganti anionici, ma dipenda invece dalla natura del legante dicarbenico. Sono stati inoltre effettuati studi elettrochimici per determinare la densità elettronica presente al centro metallico in complessi con diverso legante dicarbenico, con lo scopo di chiarire se l’efficienza del complesso sia principalmente influenzata dalle proprietà elettroniche o da quelle steriche di questo legante e di progettare così il migliore catalizzatore per la reazione. Le voltammetrie cicliche hanno mostrato che la densità elettronica al centro metallico varia a seconda del legante dicarbenico, ma che la scala di potenziali di riduzione Pd(II)-Pd(0) non è correlabile alla scala di attività catalitica. L’efficienza di questo tipo di complessi nella reazione di Fujiwara sembra quindi essere principalmente influenzata dall’ingombro sterico al centro metallico. La successiva ottimizzazione dei parametri di reazione (natura del solvente, concentrazione dei reagenti, temperatura di reazione ed utilizzo di co-catalizzatori) ha permesso di incrementare ulteriormente la selettività della reazione in condizioni di reazione blande. E’ stato infatti dimostrato che in presenza di sali di argento come co-catalizzatori (per esempio AgTFA) la reazione avviene anche a temperatura ambiente, con conversioni maggiori di quelle ottenute con palladio acetato nelle stesse condizioni di reazione. Diversamente che a 80 °C, le reazioni di isomerizzazione a trans-arilalchene (prodotto più stabile termodinamicamente) e le reazioni di idrolisi delle funzioni esteree non avvengono a temperatura ambiente, cosicché la selettività verso il cis-arilalchene viene notevolmente migliorata. Infine, sono state determinate le condizioni sperimentali adatte per estendere questo protocollo sintetico ad eterocicli aromatici, ottenendo anche in questo caso elevate rese nei prodotti. La selettività della reazione verso il prodotto desiderato è però diminuita dalla formazione di addotti eterociclo/alchino 2/1. Analisi preliminari di tipo cinetico hanno inoltre dato una prima indicazione sul tipo di meccanismo coinvolto nella reazione, che non è ancora del tutto chiarito e che potrebbe coinvolgere la metallazione elettrofilica dell’arene oppure una alchenilazione di tipo Friedel-Crafts. La legge cinetica è risultata essere del primo ordine in palladio e, nelle particolari condizioni dei reazione adottate, anche del primo ordine in arene o in alchino. Rimane da valutare la dipendenza della legge cinetica dalla concentrazione di acido, che sembra avere un ruolo importante nel meccanismo di reazione. Deve essere infatti utilizzato in largo eccesso rispetto ai substrati e probabilmente il suo ruolo principale è quello di idrolizzare la specie vinilica di palladio, proposta come intermedio catalitico in entrambi i cicli riportati in letteratura. I complessi dicarbenici di palladio(II) e platino(II) sono stati testati anche in altre reazioni di funzionalizzazione di legami C-H aromatici, come l’orto-funzionalizzazione di acetanilidi.
Song, Weifeng [Verfasser], Lutz [Akademischer Betreuer] Ackermann, and Dietmar [Akademischer Betreuer] Stalke. "Cobalt- and Nickel-Catalyzed Functionalization of Unactivated C–Hal, C–O and C–H Bonds / Weifeng Song. Gutachter: Lutz Ackermann ; Dietmar Stalke. Betreuer: Lutz Ackermann." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2013. http://d-nb.info/1044871652/34.
Повний текст джерелаBerges, 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.
Повний текст джерелаThis 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
Josefina), González María (María. "Electrocatalytic oxidation of small molecules containing C-O and C-H bonds and a method for release of microfabricated structures." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/9867.
Повний текст джерелаPellicena, Zanón Miquel. "Construcció estereoselectiva d’enllaços C-C i C-O amb enolats de titani quirals. Síntesi total de l’herboxidiè." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/132162.
Повний текст джерелаThe first Chapter of the present text deals with substrate-controlled titanium-mediated aldol reactions of chiral α-hydroxy methyl ketones. The appropriate choice of the Lewis acid and the protecting group in the α-hydroxy ketone gives access to either 1,4-anti or 1,4-syn aldol adducts in good yields (5697%) and diastereoselectivities up to ≥ 97:3 with a broad range of aldehydes. Furthermore, a sequential aldol reaction-reduction transformation from (S)-3-tert-butyldimethylsilyloxy-4-methyl-2-pentanone provides 1,2-syn-2,4-syn triols in excellent yields (9192%) and a stereochemical control which mostly relies on the aldol step of the sequence (dr 80:2094:6). The usefulness of these methodologies is proven in Chapter 2 with its application in the total synthesis of herboxidiene. Most of the carbon backbone and the required stereocentres are constructed through an aldol reaction of (S)-2-benzyloxy-3-pentanone and an aldol reaction-reduction sequence from (R)-2-tert-butyldimethylsilyloxy-3-pentanone, which are key steps in the synthesis of C1C9 fragment (17%, 10 steps) and C10C19 fragment (43%, 7 steps), respectively. Assembling of both fragments affords herboxidiene in 8% overall yield (14 steps, longest linear sequence). After a thorough study of aldol reactions of titanium enolates from α-hydroxy ketones, the reactivity of these nucleofiles is explored in other CC bond-forming reactions. In Chapter 3, the Michael addition of the titanium enolate of (S)-2-benzyloxy-3-pentanone to α,β-unsaturated ketones is developed, which provides 1,3-anti-3,4-anti adducts in excellent diastereoselectivities (dr ≥ 89:11). Finally, considering the biradical character of certain titanium enolates, in Chapter 4 the reactivity of such substrates in some CC and CO bond-forming reactions is investigated. Allylation of chiral N-acyl oxazolidinones with allyl stannanes is achieved and the corresponding adducts are obtained with excellent levels of stereocontrol (dr ≥ 97:3). Moreover, the stereoselective oxidation of chiral N-acyl oxazolidinones with TEMPO is described. The use of this stable radical leads to α-aminoxy derivatives in excellent yields and diastereomeric ratios (9095%, dr ≥ 93:7), and the stereoselective oxidation in the position of conjugate enolates is also accomplished. Elimination of the chiral auxiliary and/or reductive cleavage of the NO bond provides synthetically useful derivatives.
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.
Повний текст джерела