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1
Yasui, Hiroto. "Studies on Addition to 1-Aryl-1-alkynes and N-Alkynyl Amides." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/57271.
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Kyoto University (京都大学)0048
新制・課程博士
博士(工学)
甲第13827号
工博第2931号
新制||工||1433(附属図書館)
26043
UT51-2008-C743
京都大学大学院工学研究科材料化学専攻
(主査)教授 大嶌 幸一郎, 教授 檜山 爲次郎, 教授 松原 誠二郎
学位規則第4条第1項該当
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Edwards, Andrew R. "Polyfluorinated alkenes and alkynes." Thesis, Durham University, 1997. http://etheses.dur.ac.uk/4772/.
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The research described within this thesis may be divided into four main subject areas: 1) The use of (Z)-2H-heptafluorobut-2-ene (10) as a synthon for hexafluorobut- 2-yne (4) in Diels-Alder reactions was investigated. Novel 'one-pot' routes to a variety of bis(trifluoromethyl) substituted furan and arene derivatives were discovered, along with the synthesis of the novel diene, bis(trifluoromethyl)cyclopentadiene (46), from cyclopentadiene.2) A variety of nucleophiles were successfully reacted with (10), the products of which were identical to those that have been, or would be expected to be, formed from the reaction of the same nucleophile with (4). A novel route to a fluorinated quinoline derivative was also discovered.3) Perfluoroperhydrophenanthrene (74) was used as a 'bulking agent' to replace the hydrocarbon solvent used in halogen exchange reactions for the preparation of octafluorocyclopentene (3), chlorofluoro -pyridine, -pyrimidine, and -benzene derivatives. New 'one-pot' syntheses of hexafluorobut-2-yne (4), octafluorobut-2-ene (6) and hexafluorocyclobutene (2) were also discovered.4) Various routes were explored in an attempt to improve the present literature preparations of tetrafluoropropyne (79), including pyrolysis and elimination methods. Tetrafluoroallene (81), and trace amounts of (79), were found to be formed on the elimination of hydrogen fluoride from 2H-pentafluoropropene (5).
3
Vega, Hernández Karen de la. "Radical Germylzincation of Alkynes." Thesis, Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=http://theses-intra.upmc.fr/modules/resources/download/theses/2019SORUS072.pdf.
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Le développement d'une approche radicalaire pour la germylzincation des alcynes en tant que voie simple et générale pour la préparation de vinylgermanes polysubstitués était l'axe central de ce travail. Dans le cadre de ce projet, nous avons démontré que l'addition régio- et stéréosélective de germanium et de zinc sur la triple liaison C‒C d’ynamides terminaux et internes peut être réalisée par réaction avec un mélange d'hydrogermane et de diéthylzinc dans un processus radicalaire. La principale caractéristique de cette nouvelle approche est la possibilité de fonctionnaliser la liaison C(sp2)‒Zn créée par substitution électrophile in situ cupro- ou pallado-catalysée avec rétention de la géométrie de la double liaison. Notamment, la fonctionnalisation de la liaison C(sp2)‒Ge a également été réalisée, augmentant la valeur synthétique des germylénamides. L’approche de germylzincation radicalaire a été étendue à d’autres alcynes substitués avec un hétéroatome en α, ainsi qu’aux alcynes classiques, avec d’excellents niveaux de stéréocontrôle. Ce travail représenté une avancée importante par rapport à l’état de l’art en offrant un accès modulaire à des vinylgermanes di-, tri- et tétrasubstitués élaborés, inaccessibles jusqu’à présent par d’autres méthodes. Dans une perspective plus large, la généralisation de l’approche d’élémentozincation radicalaire a également été abordée de manière préliminaireThe development of a general radical approach for the germylzincation of alkynes as a straightforward route for the preparation of polysubstituted vinylgermanes was the central axis of this work. Within this project, we disclosed that the regio- and stereoselective addition of germanium and zinc across the C‒C triple bond of terminal and internal ynamides was achieved by reaction with a combination of a hydrogermane and diethylzinc in a radical chain process. The key feature of this new approach was the possibility of using the C(sp2)‒Zn bond created as linchpin for subsequent in situ Cu(I)- or Pd(0)-mediated electrophilic substitution with retention of the double bond geometry. Notably, functionalization of the C(sp2)‒Ge bond was also achieved, enhancing germylenamides’ synthetic value. The radical germylzincation approach was further extended to other α-heteroatom-substituted alkynes, as well as more challenging conventional alkynes with excellent levels of stereocontrol. This work marked an important advance over prior art by offering modular access to elaborated di-, tri- and tetrasubstituted vinylgermanes that were not accessible by other methods thus far. From a wider perspective, the generality of the radical elementozincation approach was also preliminarily considered
4
Guo, Xun-Xiang. "Studies on Rhodium-Catalyzed Alkynylation of Alkynes, Allenes and Conjugate Enones with Terminal Alkynes." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/124355.
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Zargarian, Davit. "Palladium-catalyzed carbonylation of alkynes." Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/7555.
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This thesis describes the palladium-catalyzed carbonylation of alkynes with formic acid. Terminal alkynes react with formic acid in the presence of catalytic amounts of Pd(OAc)$\sb2$ and suitable phosphine ligands (120 psi of CO gas pressure, 100-110$\sp\circ$C) to produce the unsaturated carboxylic acids CR(COOH)=CH$\sb2,$ 1, and (E)-CHR=CH(COOH), 2. The combined yields of 1 and 2 for various R's range from 60 to 90%. The regioselectivity is approximately 90:10 in favour of 1 when R is a phenyl or a straight chain alkyl group; 2 is the favoured product when R is t-Bu and the exclusive one when R is SiMe$\sb3.$ Under similar conditions, internal alkynes react with formic acid to produce the unsaturated carboxylic acids (E)-CR(COOH)=CHR$\sp\prime$, 3, and (E)-CHR=CR$\sp\prime$(COOH), 4, also in 60-90% combined yields. The regioselectivity of this reaction, however, is not as high as for terminal alkynes. Oxalic acid can be used instead of formic acid in both of these reactions. The most suitable phosphine ligands for alkyne hydrocarboxylation in the present system are PPh$\sb3$ and dppb (1,4-bis(diphenylphosphino)butane). In some cases, using a mixture of these two ligands remarkably improves the reaction yields; the implications of such ligand synergism are discussed. On the basis of deuterium labelling studies and other experimental results, a reaction mechanism has been proposed which involves the addition of the O-H bond of formic acid to form a cationic hydrido(alkyne) intermediate. This intermediate is thought to undergo a sequence of reactions, including hydride and CO insertions, to give the acid product and regenerate the active catalyst. Terminal alkynes undergo dicarbonylation upon reacting with formic acid and/or water in a catalytic system consisting of $\rm PdCl\sb2/CuCl\sb2/O\sb2/CO$ (room temperature, atmospheric pressure); the products are monosubstituted maleic anhydrides and the corresponding maleic and fumaric acids in 30-75% combined yields. The product distribution is influenced by both the steric bulk of the alkyne substituent and the amount of water present in the reaction medium. Internal alkynes are unreactive in this system. Among the solvents tested, THF is the most suitable one. Phosphines and phosphites completely inhibit the reaction. In contrast to most systems in which CuCl$\sb2$ acts as the principal oxidant for converting Pd(0) to Pd(II), the role of CuCl$\sb2$ in the present system seems to be secondary to that of oxygen. For instance, modest catalytic turnovers are observed in the absence of CuCl$\sb2$, whereas no catalysis occurs if oxygen is excluded from the system, even in the presence of excess CuCl$\sb2$. These and other observation are rationalized by invoking various oxidation schemes involving oxygen as the main oxidant. The role of CuCl$\sb2$ is thought to be one of facilitating the catalysis by forming a heterometallic Cu/Pd complex.
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Lawson, James. "The reactivity of borocations with alkynes." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/the-reactivity-of-borocations-with-alkynes(71be0441-dae2-4f4f-b570-a02000bdf7de).html.
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It has been found that by combining various borocations or neutral electrophilic boranes with a multitude of alkynes, interesting and often highly selective borylation reactivity is observed. The reactions can be loosely categorised as de-(elemento)boration of the alkyne, haloboration and carboboration. Direct alkyne de-(elemento)boration was achieved as both dehydroboration and desilylboration, generating a selection of borylated alkynes. Other examples of more complicated alkyne borylation were also observed, such as the boroamination of TMS-ethylene. Upon discovering that 2-N,N-dimethylaminopyridine ligated dichloro-boronium salt underwent selective 1,2-haloboration with a range of terminal alkynes, and that the dibromo-analogue could haloborate a limited number of internal alkynes, the more Lewis acidic borenium salt [Cl2B(2,6-lutidine)][AlCl4] was synthesised and reacted with a series of internal alkynes to give haloborated products. These included dialkyl and diaryl internal alkynes containing a range of functional groups including thioether, methoxyphenyl, vinyl and halide. Each proceeded with excellent stereo- and regio-selectivity, with the boron and the halide added mutually cis, and the regioselectivity determined by the electronically most stable form of the carbocation intermediate. The initial dihalovinyl borane products were esterified in-situ to provide the more stable pinacol boronate esters. The elementoboration method was expanded via modification of the borocations to include different transfer groups that, upon reaction with trimethylsilyl-substituted alkynes, underwent 1,1-carboboration, with migration of the TMS-group. This method also provided access to a small selection of borylated dienes, resulting from reactions with excess alkyne. It was also shown that some neutral boranes reacted analogously with certain TMS-alkynes, albeit with limitations on scope. In addition to this, two types of 1,2-carboboration were discovered. The first involved intercepting products from alkyne haloboration with a TMS-alkyne, undergoing a vinylboration to produce 1-boradiene products. The second was an example of an intermolecular trans carboboration, where the initially formed vinyl carbocation is intercepted by a thiophene.
7
Thompsett, Andrew Robert. "The coordination chemistry of unusual alkynes." Thesis, University of Warwick, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302650.
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Warner, Andrew. "Borylative cyclisation of alkynes using BCl3." Thesis, University of Manchester, 2017. https://www.research.manchester.ac.uk/portal/en/theses/borylative-cyclisation-of-alkynes-using-bcl3(7a4e56f3-e8c6-4c68-97ec-4596ef5e0ce2).html.
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Boron trichloride, a cheap and commercially available Lewis acid, has been demonstrated to activate alkynes possessing appropriate nucleophiles, facilitating borylative cyclisation. This reaction furnishes polycyclic compounds possessing a new C(sp2)-B bond externally to the newly formed ring (through concomitant C-C and C-B bond formation). The RBCl2 intermediates generated from cyclisation were esterified with pinacol to furnish air/moisture stable boronic esters. This methodology has been applied to the following classes of starting materials: 1,4-disubstituted but-1-ynes (including N- and O- linked analogues), 2-alkynylanisoles, 2-alkynylthioanisoles and 1,2-bis(alkynyl)benzenes. Thus, borylated scaffolds such as dihydronaphthalenes, dihydroquinolines, 2H-chromenes, benzofurans, benzothiophenes, dibenzopentalenes and benzofulvenes have been synthesised. A variety of functionalities (e.g. amines, esters, nitriles) were tolerated by the reaction, with a number of substrates cyclised on either a gram scale, or under ambient conditions, demonstrating the robust nature of this methodology. An oxidation reaction with [Ph3C][BF4] was carried out on some of the borylated dihydronaphthalene compounds to obtain borylated naphthalenes. Suzuki-Miyaura cross-coupling reactions were carried out on certain borylated cycles to furnish new C-C bonds and generate analogues of established pharmaceuticals such as Nafoxidine or Raloxifene, demonstrating the synthetic value of these borylated cycles. Additionally, a one-pot borylative cyclisation/Suzuki-Miyaura cross-coupling reaction was also developed. Throughout this investigation, alternative reactivity has been observed when using BCl3 to activate certain alkynes, including intermolecular 1,2-trans-carboboration and a rare example of N- and O-directed 1,2-trans-haloboration. Additionally, multiple borylative cyclisations have been carried out on an appropriate alkyne to obtain a B-doped polyaromatic hydrocarbon (PAH), which has potential material-based applications.
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Maah, M. J. "Transition metal complexes derived from phospha-alkynes." Thesis, University of Sussex, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381631.
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Greenhalgh, Mark David. "Iron-catalysed hydrofunctionalisation of alkenes and alkynes." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/17624.
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The iron-catalysed hydrofunctionalisation of alkenes and alkynes has been developed to give a range of functionalised products with control of regio-, chemo- and stereochemistry. Using a bench-stable iron(II) pre-catalyst, the hydrosilylation, hydroboration, hydrogermylation and hydromagnesiation of alkenes and alkynes has been achieved. Iron-catalysed hydrosilylation, hydroboration and hydrogermylation of terminal, 1,1- and 1,2-disubstituted alkyl and aryl alkenes and alkynes was developed, in which the active iron catalyst was generated in situ (Scheme A1). Alkyl and vinyl silanes and pinacol boronic esters were synthesised in good to excellent yield in the presence of a range of functional groups. Catalyst loadings as low as 0.07 mol% were demonstrated, along with catalyst turn-over frequencies of up to 60 000 mol h−1. The iron-catalysed formal hydrocarboxylation of a range of styrene derivatives has been developed for the synthesis of α-aryl carboxylic acids using carbon dioxide and ethylmagnesium bromide as the stoichiometric hydride source (Scheme A2). Detailed mechanistic studies have shown this reaction proceeds by iron-catalysed hydromagnesiation to give an intermediate benzylic organomagnesium reagent. The nature of the active catalyst and reaction mechanism have been proposed.
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An, Juzeng <1990>. "Gold Catalyzed Functionalization Of Alkynes And Allenamides." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9167/1/PhD%20thesis-Juzeng%20An-32th.pdf.
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The gold(I)-catalyzed chemoselective dearomatization of β-naphthols is reported through a straightforward approach via [3,3]-sigmatropic rearrangement /allene-cyclyzation cascade processes. Easily accessed naphthyl-propargyl ethers and derivatives in this work are employed as starting materials. Delightfully, an array of deoramatized dyhydrofuryl -naphthalen-2(1H)-ones featured densely functional groups are obtained in high yields (up to 98%) in 10 min reaction time under extremely mild reaction conditions like reagent grade solvent and exposure to air. The potential of accessing to high enantioselectivety on the dearomatized dyhydrofuryl- naphthalen-2(1H)-ones is also approved by the good ee (65%) relying on (R)-xylyl- BINAP(AuCl)2. In addition, complete theoretical elucidation of the reaction pathway is also proposed which addresses a rationale for essential motivation such as regio- and chemoselectivity.
Moreover, an efficient gold catalyzed intermolecular dearomatization of substituted β-naphthols with allenamides is presented here. PPh3AuTFA (5 mol %) approves the efficient dearomatively allylation protocol under mild conditions and exhibits high tolerance on substrates scope (24 examples) in good to excellent yield accompanied with high regioselectivity and stereoselectivity. Moreover, the synergistic catalytic system also highlight the synergistic function between the [PPh3Au]+ (π-acid) and TFA− (Lewis base). At last, a new chiral BINOL phosphoric acid silver salt is successfully synthesized and used as the chiral counter anion, which strongly promotes the enantioselectivity (up to 92%).
At last but not least, crucially, SmI2 induced enantioselective formal synthesis of strychnine, a complex alkaloid and a classical target used to benchmark new synthetic methods is developed. Enantioselective dearomatising radical cyclisation on to the indole unit and further ET will then give organosamarium that is quenched diastereoselectively by the ester to deliver Strychnine in 7 steps.
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Mule, R. "Metal-mediated intramolecular cyclization of pyridino-alkynes." Thesis(Ph.D.), CSIR-NCL, 2021. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/5973.
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Wigginton, James Richard. "The reactions of diynols at a diruthenium centre." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274641.
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Lai, Kwong Wah. "Studies on syntheses, reactions, and biomedical applications of functionalized alkynes /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CHEM%202004%20LAI.
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Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2004.Includes bibliographical references (leaves 333-356). Also available in electronic version. Access restricted to campus users.
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Zanini, Margherita. "Transition metal-catalyzed reactions of heteroatom-substituted alkynes." Doctoral thesis, Universitat Rovira i Virgili, 2020. http://hdl.handle.net/10803/670898.
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La catàlisi homogènia d'or(I) és una eina per a la construcció de complexitat molecular mitjançant l'activació selectiva
d'enllaços múltiples C-C. El nostre grup ha desenvolupat una sèrie de reaccions d'alquins amb alquens catalitzades
per or(I) tant en forma intramolecular com intermolecular. Aquestes reaccions s’inicien amb l'atac nucleofílic del doble
enllaç a l'alquí per formar un intermedi tipus ciclopropil carbé d'or(I) que evoluciona per donar diferents productes. En
aquesta tesi doctoral es descriu una sèrie de noves reaccions intermoleculars de alquens amb alquins substituïts amb
heteroàtoms catalitzades per or(I). A més, es presenten els estudis mecanístics corresponents, realitzats mitjançant
experiments i càlculs DFT.
En les reaccions entre bromolaquins i alquens catalitzades per or(I), inicialment es genera un 1-brom ciclopropil carbé
d'or(I) que evoluciona a través d'un catió bromoni ciclic per formar un vinilidè d'or(I) o en un catió vinilidilareni
estabilitzat per or. Els càlculs DFT demostren que aquests dos intermedis són confòrmers de la mateixa espècie però
tenen diferent reactivitat. D'una banda, el vinilidè d'or(I) pot participar en reaciones d'activació C-H o de hidroarilació,
mentre que el catió vinilidilareni participa en transposicions 1,2 de l'areni per a formar un triple enllaç.
A més, els alquinil èters terminals participen en cicloaddicions [2 + 2] amb alquens per formar ciclobutens que poden
convertir-se fàcilment en les corresponents ciclobutanones.La catálisis homogénea de oro(I) es una poderosa herramienta para la construcción de complejidad molecular en condiciones suaves mediante la activación selectiva de enlaces múltiples C-C. Nuestro grupo ha desarrollado una serie de reacciones de alquinos con alquenos catalizadas por oro(I), tanto de forma intramolecular como intermolecular. Estas reacciones comienzan con el ataque nucleofílico del doble enlace al alquino para formar un intermedio tipo ciclopropil carbeno de oro(I), que evoluciona para dar lugar a diferentes productos. En esta Tesis Doctoral se describen una serie de nuevas reacciones intermoleculares entre alquenos y alquinos sustituidos con heteroátomos catalizadas por oro(I). Además, se presentan los estudios mecanísticos correspondientes, realizados mediante experimentos y cálculos DFT. En las reacciones entre bromoalquinos y alquenos catalizadas por oro(I), inicialmente se genera un 1-bromo ciclopropil carbeno de oro(I) que evoluciona a través de un catión bromonio cíclico para formar un vinilideno de oro(I) o un catión vinilidilarenio estabilizado por oro. Los cálculos DFT demuestran que estos dos intermedios son confórmeros de la misma especie pero tienen diferente reactividad. Los vinilidenos de oro(I) pueden participar en reacciones de activacion C-H o de hidroarilación, mientras que los cationes vinilidilarenio participan en transposiciones 1,2 del areno para formar enlaces triples.
Homogeneous gold(I) catalysis is a powerful tool for the construction of molecular complexity under mild conditions by mean of the selective activation of C-C multiple bonds. Our group developed a series of gold(I)-catalyzed reactions of alkynes with alkenes both in intramolecular and intermolecular settings. These reactions start with the nucleophilic attack of the double bond on the alkyne to form a cyclopropyl gold(I) carbene intermediate that than rearranges into a variety of products. In this Doctoral Thesis we present a series of new gold(I)-catalyzed intermolecular reactions of heteroatom-substituted alkynes with alkenes and the mechanistic investigation we performed by means of experimental work and DFT calculations. In the gold(I) catalyzed reactions of bromoalkynes with alkenes, the 1-bromo-cyclopropyl gold(I) carbene initially formed rearranges into gold(I) vinylidenes and vinylidenephenonium gold(I) cations passing through a cyclic bromonium intermediate. DFT calculations demonstrated that these two reactive intermediates are conformers of the same species but have different reactivity. On one side gold(I)-vinylidenes can undergo hydroarylation or C-H insertion, while vinylidenephenonium gold(I) cations easily undergo 1,2-aryl shift forming a triple bond. Moreover, we found that terminal alkynyl ethers are undergoing efficiently [2+2] cycloaddition with alkenes to form cyclobutene derivatives that can be easily transformed into the corresponding cyclobutanones.
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Low, Eddy Wai Mang. "Reactions towards enediyne heterocycles and nitroimidazoles incorporating alkynes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0003/NQ41217.pdf.
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Wang, Jun. "Alkynes and allenes as precursors of complex heterocycles." Thesis, University of Leeds, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275797.
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Guo, Zijian. "Developing unstrained alkenes and alkynes for bioorthogonal chemistry." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/289423.
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Bioorthogonal reactions, due to its excellent selectivity and time-efficiency, have emerged as a popular tool for protein and cell probing. Among all the bioorthogonal reactions, the inverse electron-demand Diels-Alder reaction (IEDDA) reaction has its advantage of bearing the fastest kinetics. Although the IEDDA reaction drew considerable attention in chemical biology in the last decade, challenges lie in finding the suitable dienophiles. Strained dienophiles, for example, trans-cyclooctene derivatives, can undergo ultrafast IEDDA reactions and therefore have been extensively developed. Unstrained alkenes and alkynes, however, have not been well investigated as IEDDA handles. In general, unstrained dienophiles are more straightforward to synthesise compared with strained dienophiles, therefore they are more accessible to researchers. In addition, the absence of a highly reactive bond makes unstrained dienophiles inert to biological nucleophiles, which allows effectively cellular labelling. In this dissertation, I described three different unstrained dienophiles for different biological purposes. Allyl handle is thiol-stable and non-toxic, which was utilised to label apoptotic cells in a pre-targeting manner. Enol ethers can react with tetrazines to decage protected amino acids and prodrugs. Potassium arylethynyltrifluoroborate, as a novel dienophile, was shown to react fast with pyridyl tetrazines controllably and this new IEDDA was applied to label proteins site-selectively and to fluorescently label two proteins orthogonally. In addition to IEDDA reactions, other bioorthogonal reactions were also developed using these versatile unstrained handles. Allyl-bearing amino acids and proteins can undergo an acetophenone-mediated hetero-[2+2] photocycloaddition with maleimide derivatives, expanding the toolbox of photo-triggered chemistry for protein modification. The potassium arylethynyltrifluoroborate handle was also found reactive in copper(I)-catalyzed alkyne-azide cycloaddition reaction (CuAAC) and showcased the huge potential for protein labelling and multicolour cellular labelling.
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STADERINI, Samuele. "Photoinduced hydrothiolation and hydrophosphonylation of alkenes and alkynes." Doctoral thesis, Università degli studi di Ferrara, 2014. http://hdl.handle.net/11392/2389036.
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Hydrofunctionalization of terminal double or triple bonds have become classical ligation tools for facile assembly of building blocks into larger molecules especially because comply Sharpless’ prerequisite to be considered “click-chemistry” reactions. In particular the free-metal photoinduced radical thiol-ene (TEC) and thiol-yne (TYC) couplings are well-known to be atom economy, high-efficient, catalyzed only by light and completely regioselective. If both TEC and TYC have already been studied on simple substrates as linear terminal alkenes or alkynes, only few researches have been carried out about particular molecules as protein, peptides and endo-glycals. Hydrothiolation of protein, peptides and aminoacids has been studied to obtain a double different substitution of the peptidic scaffold with one carbohydrate and one marker (fluoresceine or biotine) using TYC. A new technique to synthesize S-disaccharides has been developed starting from different glycals and thio-glucose, demonstrating the efficiency of TEC on internal internal double bonds.
The successful work about hydrothiolation of different substrates has pushed us to study both hydrophosphonylation of alkenes and alkynes starting from the same conditions of TEC and TYC reactions. The different reactivity of the functionalization agent (thiol or H-phosphonate) has resulted in different conditions for the addition to double bonds, but not in a loss of efficiency o regioselectivity. On the other hand the addition on a triple bond has resulted to be ineffective and to stop at the internal double bond intermediate. A thiol-ene coupling on this intermediate, formally a vinyl phosphonate, gives equilibration to E form of the alkene without traces of hydrothiolation adducts.
It is well known that multivalent effect is a key factor in supramolecular chemistry and it governs many biological interactions, in particular in the relationship between pathogenic microorganisms and their host that involves protein–glycan recognition. The affinity of a multivalent cluster is highly dependent on the combination of the carbohydrate head with the cluster core and the spacer between them; several families of multivalent bioactive molecules have been developed by a large numbers of groups all around the world using disparate synthetic techniques. Thiol-Ene (TEC) and Thiol-Yne (TYC) couplings have been chosen as ligation tool for the synthesis of a variety of multivalent biomolecules containing carbohydrates or peptidic termini supported on different bio-inactive clusters as dendrimers and the rigid silica cube known as POSS (polyhedral oligomeric silsesquioxane). Both TEC and TYC are highly efficient, regioselective and atom economy reactions that, moreover, permit us to avoid purification problems due to metal catalysis or to use large excess of reagents to have a complete substitution on the central core. In fact all the reactions have been carried out with success, high yield and without by-products of any kind. Affinity toward specific target of this large library of compounds has been tested by Enzyme-Linked Lectin Assay (ELLA) and results from good to excellent have been found in all classes of compounds.
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Hoenigman, Rebecca Lee. "Theoretical and experimental investigations of diradicals, pyramidalized alkenes, and bent alkynes /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/8580.
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Trono, Corazon. "Transition metal catalyzed synthesis of glycoclusters from sugar alkynes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ58515.pdf.
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Adams, Kerry John. "The chemistry of alkynes at a trinuclear metal centre." Thesis, University of Bristol, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357652.
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He, Jinglei. "Synthesis of fluorinated heterocycles by electrophilic cyclisations of alkynes." Thesis, University of Leicester, 2016. http://hdl.handle.net/2381/42538.
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Fluorinated heterocyclic compounds are a highly desirable target for the pharmaceutical industry because heterocyclic compounds often form the core structure in drug candidate molecules and the incorporation of fluorine often enhances their biological activity. The aim of this project was to design new and efficient procedures to fluorinated heterocycles using aromatic alkynes containing internal nucleophiles. In Chapter 2 a series of known and new alkynes were synthesised by Sonagashira reactions of terminal alkynes with aryl iodides and the reactivity of these alkynes with electrophilic fluorinating reagents was studied. The alkynes were reacted with Selectfluor to generate difluorinated ketones and a diketone byproduct was also produced in some of the reactions. The introduction of an ortho-substituent (-NO2, -CH2OH, -CHO, -CH2OAc) on the aryl rings had a significant impact on these reactions and, in most cases, no difluoroketone products could be isolated. In Chapter 3 iodocyclisations of the alkynes with internal nucleophiles were studied as the model reactions for electrophilic cyclisation. When Py2I+BF4- was used as the electrophilic iodinating reagent, 6-membered rings were normally obtained. However, when iodine was used as the electrophilic iodinating reagent, either 6- or 5-membered rings could be obtained as the main products depending on the internal nucleophile. For example, the fluoroalkylated secondary alcohols underwent 6-endo-dig cyclisations with Py2I+BF4-, whilst the reaction of the same substrate with iodine gave predominately the (E) 5-exo-dig iodocyclised products. Palladium-catalysed protocyclisations with a range of aromatic alkyne substrates, including secondary and tertiary alcohols, carboxylic acid and secondary amine, are described in Chapter 4. A new fluorocyclisation for tertiary alcohols using N-fluorobenzenesulfonimide and silver nitrate was developed successfully and three different types of fluorinated products (monofluorinated alcohol, difluorinated alcohol and monofluorinated alkene) were obtained depending upon the tertiary alcohol and the amount of N-fluorobenzenesulfonimide.
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Yoshida, Hiroto. "Studies on the Transition Metal-Catalyzed Carbostannylation of Alkynes." Kyoto University, 2001. http://hdl.handle.net/2433/150653.
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Hiibner, Kristin. "The reactivity of iridium metallacyclopentadiene complexes toward terminal alkynes /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9820850.
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Hirata, Yasuhiro. "Studies on Nickel-Catalyzed Cyanofunctionalization of Alkynes and Dienes." 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/77958.
Full textAbstract:
Kyoto University (京都大学)0048
新制・課程博士
博士(工学)
甲第14584号
工博第3052号
新制||工||1454(附属図書館)
26936
UT51-2009-D296
京都大学大学院工学研究科材料化学専攻
(主査)教授 檜山 爲次郎, 教授 大嶌 幸一郎, 教授 松原 誠二郎
学位規則第4条第1項該当
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Kanyiva, Kyalo Stephen. "Studies on Nickel-catalyzed Hydroarylation and Hydrocarbamoylation of Alkynes." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120819.
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Walker, Alan Philip. "Some aspects of the chemistry of co-ordinated alkynes." Thesis, University of Bath, 1995. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296298.
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Maza, Johnathan Charles. "Expanding The Scope of Terminal Alkynes in Chemical Biology." W&M ScholarWorks, 2016. https://scholarworks.wm.edu/etd/1477068470.
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The terminal alkyne is one of the most widely used chemical moieties in chemical biology. Thanks to the relative absence of this functional group in biology, it has become a widespread functional handle for a plethora of biorthogonal chemistries. Our group has extended the scope of this functionality by developing a biological variant of the Glaser-Hay coupling, which brings together two terminal alkynes to form a diyne linkage. However, our initial findings revealed that the chemistry is plagued by protein degradation due to a deleterious copper(II) hydroxyl intermediate. Herein we extend the scope of the terimanl alkyne be developing a biological variant of the Cadiot-Chodkiewicz coupling, which brings together a bromoalkyne and a terminal alkyne to form a diyne linkage. Unlike the Glaser-Hay, the Cadiot-Chodkiewicz is thought to be net redox neutral. We found that this chemistry is biologically compatible and does indeed reduce copper(II)-mediated cytotoxicity while increasing rates of diyne formation. Finally, we extend our findings on diyne-forming chemistries by applying this conjugation to a variety of projects, ranging from undergraduate teaching labs, bioconjugate preparation, and protein function, thereby expanding the scope of this conjugation strategy.
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Brayshaw, Simon Keith. "Metal complexes bearing pendant alkynes and metal complexes of N-heterocyclic carbenes." University of Western Australia. School of Biomedical and Chemical Sciences, 2004. http://theses.library.uwa.edu.au/adt-WU2005.0017.
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This thesis is comprised of two parts. The first part describes the synthesis of cyclopentadienyltungsten complexes containing a pendant alkyne group (I), and the subsequent photo-induced intramolecular coordination of the alkyne, forming complexes such as II. Compounds containing intramolecularly coordinated alkynes are rare, and this is the first example using cyclopentadiene as the core ligand. The second part describes the synthesis and structural characterisation of a number of novel metal complexes containing N-heterocyclic carbene ligands, some containing particular functionality for taylored applications. New methods were used to form complexes of rhodium, iridium, silver and gold (eg. III, IV). Structural and spectroscopic properties of the complexes were correlated with electronic characteristics of the ancillary ligands. A number of rhodium and iridium complexes (eg. IV) derived from imidazolium-linked cyclophanes were synthesised and structurally characterised. Complexes of N-heterocyclic carbenes with pendant ionic groups were synthesised, and a preliminary examination of their catalytic activity in water was performed. N-Heterocyclic carbenes complexes containing an electron withdrawing nitro group were synthesised and the effect of the nitro group on metal-ligand bonding was examined.
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Shiu, Hoi-yan Fiona, and 邵凱恩. "Cleavable cysteine modification by electron-deficient alkynes and molecular imaging of cysteine and homocysteine." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B45996325.
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Banerjee, Sanjukta. "Titanium-catalyzed additions of substituted hydrazines to alkynes catalyst design, mechanistic studies, and applications in heterocycle synthesis /." Diss., Connect to online resource - MSU authorized users, 2008.
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García, Barrado Alejandro. "New Methodologies for the Regio- and Stereoselective Electrophilic Cyanation of Alkynes." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://hdl.handle.net/11858/00-1735-0000-002E-E549-8.
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Hunt, Ashley D. "Intramolecular Cope-type Hydroamination of Alkenes and Alkynes Using Hydrazides." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19881.
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Nitrogen-containing molecules are ubiquitous in both natural products and pharmaceutical drugs, thus an efficient method for the formation of these motifs is of great importance. Hydroamination, that is the addition of an N-H bond across an unsaturated carbon-carbon bond of an alkene or alkyne, stands out as a potential approach to obtain such molecules. To date, most research in this area relies on transition-metal catalysis to enable such reactivity. In efforts directed towards metal-free alternatives, we have developed a simple, metal-free hydroamination of alkenes using hydrazides. Further investigation into the corresponding reactivity of alkynes with hydrazides has provided access to novel azomethine imine products. In Chapter 2, expansion of the substrate scope with respect to the intramolecular hydroamination of alkenes using hydrazides, as well as studies directed towards elucidation of the mechanism of this reaction will be presented. The intramolecular hydroamination of alkynes using hydrazides and methods to access and isolate the azomethine imine products formed will be discussed in Chapter 3.
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Maudru, Elise. "The synthesis of cyclohexanes by radical cyclisation of carbohydrate alkynes." Thesis, University of Sunderland, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300351.
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Reeve, Carolyn. "Some chemical consequences of II-donation by co-ordinated alkynes." Thesis, University of Bristol, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375912.
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King, Andrew. "Intermolecular hydrophosphination of alkynes and dehydrocoupling studies using iron catalysts." Thesis, University of Bath, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.767588.
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Iron β-diketiminate complexes have great potential as catalysts. Previous work into the coordination chemistry of complexes bearing the β-diketiminate ancillary ligand (Chapter 1) attest to the useful properties of these complexes in catalysis. A handful of literature reports on catalytic systems hint that this could be further extended. Hydrophosphination is a growing field that continues to generate a lot of interest from industry and academia alike. The aims of this project are to investigate hydrophosphination reactions with iron β-diketiminate complexes, to achieve high degrees of regioselectivity from these sterically encumbered complexes and to investigate iron catalysed dehydrocoupling reactions. A combination of synthetic and mechanistic methodologies will be employed in order to achieve definitive insight via NMR spectroscopic analysis, kinetic studies and solid state crystallography. Initial work presented herein (Chapter 2) will focus on the synthesis of iron(II) β-diketiminate complexes. Previously reported literature methods will be explored in order to determine an optimum procedure to use these precatalyst complexes. Initial investigations into hydrophosphination activity of these iron species will then be explored with alkenes. Results of these studies led to serendipitous findings and unexpected results in phosphine dehydrocoupling. The scope of this reactivity was then probed and mechanistic considerations taken into account with findings detailed herein. Radical catalysed reactivity observed will be further discussed. Solvent selectivity will then be discussed with a simple yet highly effective solvent change yielding a complete shift in catalytic activity. Further studies (Chapter 3) highlight the orthogonal reactivity of iron(II) β-diketiminate complexes in hydrophosphination catalysis. Less electronically activated and more atypical substrates have been investigated to determine their activity in hydrophosphination reactions. The synthesis of phosphinoalkenes and phosphinoalkynes for cyclic intramolecular hydrophosphination reactions are detailed along with their catalytic activity. Preliminary mechanistic studies are discussed with radical species again proving crucial to catalytic activity. Selective intermolecular hydrophosphination reactions have been investigated with alkynes. A solvent based switch can be employed wherein the regioselectivity of the reaction is completely altered. Substrate scope, mechanistic considerations and potential future applications are examined in full detail. Dehydrocoupling catalysis can be extended in scope (Chapter 4) from iron catalysed phosphine homocoupling reactions to heterocoupling reactions. Phosphine-silane dehydrocoupling is found to be highly selective for the formation of silaphosphanes, preliminary mechanistic insight and reaction scope is discussed. Analogous amine-silane dehydrocoupling is explored in full. The substrate scope offers insight into reactivity and potential further applications in sequential and tandem catalysis. In depth mechanistic insight is discussed with kinetic analyses. Iron-amido complexes are observed to react in a metathesis mediated cycle via iron hydride species. Finally catalytic alcohol-silane dehydrocoupling is investigated as a synthetic route to protected natural products in organic synthesis. Unsaturated silazanes are potential targets for further dehydrocoupling reactions. Catalytic reactions with pinacolborane led to highly facile desilylation reactions (Chapter 5). Mechanistic considerations hint that the reactions occur via σ-bond metathesis could through iron hydride species. Desilylation activity is then extended to siloxanes and a model developed with potential applications in the depolymerisation of polysilazanes and polysiloxanes.
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Cremonesi, Alex. "Gold catalysed intermolecular atom transfer reactions on heteroatom-substituted alkynes." Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4083/.
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In this thesis the development of several novel gold-catalysed transformations are reported. Two intermolecular atom transfer processes have been designed and developed to access gold carbenoid reactivity. The latter reactive species allowed the synthesis of various α,ß-unsaturated carboxylic acid derivatives and trisubstituted oxazoles. Numerous nitrogen- and oxygen substituted alkynes have been prepared and employed in oxygen transfer processes promoted by gold complexes. Using pyridine \(N\)-oxide, both ynamides and ynol ethers underwent regioselective intermolecular oxidation reactions under mild gold catalysis conditions. During the transformation, an α-oxo gold carbenoid intermediate is accessed which develops through a rapid 1,2-insertion reaction to yield α,ß -unsaturated imides and vinylogous carbimates. The strategy has proved to be a valid alternative to the use of hazardous α-oxo diazo compound when carbene reactivity is desired. Appling a similar strategy, \(N\)-imido pyridonium ylides have been used as an \(O,N\)-dipole onto gold activated ynamides and ynol ethers. The overall [3+2] cyclisation occurred through a nitrene transfer process followed by a cycloisomerisation step. Under this approach, ynamides and ynol ethers have been converted into highly functionalised trisubstituted oxazoles. The mild gold catalysis conditions allowed the use of a wide range of functionality. Moreover, the α-imido gold carbenoid involved as a reaction intermediate displayed the possibility to utilise such protocol to access α-imido carbene reactivity
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Miller, Karen M. (Karen Marie). "Selective, nickel-catalyzed carbon-carbon bond-forming reactions of alkynes." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32482.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2005.Vita.
Includes bibliographical references.
Catalytic addition reactions to alkynes are among the most useful and efficient methods for preparing diverse types of substituted olefins. Controlling both regioselectivity and (EIZ)- selectivity in such transformations presents a significant challenge. In reactions that also involve the creation of a new stereocenter, the development of enantioselective processes is highly desirable. Several novel, nickel-catalyzed carbon-carbon bond-forming reactions of alkynes that display excellent regioselectivity and (E/Z)-selectivity are described. These reactions afford synthetically useful allylic and homoallylic alcohols, often with high enantioselectivity. A highly enantioselective method for the nickel-catalyzed reductive coupling of alkynes and aldehydes has been realized using the commercially available (+)- neomenthyldiphenylphosphine as a chiral ligand. Allylic alcohols are afforded with complete (E/Z)-selectivity, generally >95:5 regioselectivity, and in up to 96% ee. In conjuction with ozonolysis, this process is complementary to existing methods of enantioselective [alpha]-hydroxy ketone synthesis. In alkene-directed, nickel-catalyzed reductive couplings of 1,3-enynes with aldehydes and epoxides, the conjugated alkene dramatically enhances reactivity and uniformly directs regioselectivity, independent of the nature of the other alkyne substituent (aryl, alkyl (1°, 2°, 3°)) or the degree of alkene substitution (mono-, di-, tri-, and tetrasubstituted). The highly substituted 1,3-diene products are useful in organic synthesis and, in conjunction with a Rh-catalyzed, siteselective hydrogenation, afford allylic and homoallylic alcohols that previously could not be prepared in high regioselectivity (or at all) with related Ni-catalyzed alkyne coupling reactions. Enantiomerically enriched terminal epoxides can be employed to afford enantiomerically enriched homoallylic alcohols. P-chiral, monodentate ferrocenyl phosphine ligands are efficient promoters of catalytic, asymmetric reductive coupling reactions of 1,3-enynes with aromatic aldehydes and with ketones. The latter represents the first catalytic intermolecular reductive coupling of alkynes and ketones, asymmetric or otherwise, to be reported. Both of these methods afford chiral 1,3-dienes in excellent regioselectivity and modest enantioselectivity. Nickel-catalyzed reductive couplings of 1,6-enynes and aldehydes also display very high (>95 : 5) regioselectivity. Use of a monodentate phosphine as an additive leads to formation of the opposite regioisomer in equal and opposite selectivity (5: >95). These results provide strong evidence for an interaction between the remote alkene and the metal center during the regioselectivity-determining step.
by Karen M. Miller..
Ph.D.
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Janson, Pär. "Oxidative Trifluoromethylation and other Functionalization Reactions of Alkenes and Alkynes." Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-103064.
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This thesis concerns the use of various potent oxidants in organic synthesis. The main focus is directed at selectively introducing trifluoromethyl groups into compounds containing double or triple bonds. All reactions proceed under mild conditions and can in most cases be performed on the bench-top. We have developed three different procedures for transformations of activated alkenes and alkynes as well as quinones. In paper I the selective introduction of a trifluoromethyl group together with an oxygen functionality to double and triple bonds is demonstrated. Paper II is focused on the related chemoselective cyanotrifluoromethylation in which a cyano group is added instead of the oxygen functionality. Paper III describes a new procedure for C–H trifluoromethylation of quinones. Our studies on the mechanistic aspects of the above reactions are described in Paper IV. In these studies we investigated the ligand and substituent effects in Cu-catalyzed reactions. Paper V is focused on a conceptually new palladium-catalyzed allylic C–H acyloxylation of olefins under oxidative conditions. The procedure uses an inexpensive, safe and environmentally benign oxidant, sodium perborate, which is activated with acetic anhydride.At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Submitted.
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Garba, Mustapha Danlami. "Valorisation of alkanes and alkynes by transhydrogenation in petrochemical processes." Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/8719/.
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The production of high premium fuel is an issue of priority to every refinery. The trans-hydrogenation process was devised to convert two low value refinery cracked products to premium products; the conversion processes involve the combination of dehydrogenation and hydrogenation reactions as a single step process. The low value refinery products (i.e. alkanes and alkynes or alkadienes) have been converted to alkenes (olefins) by trans-hydrogenation using catalysts system based on VOx, CrOx and Pt all supported on alumina. Although trans-hydrogenation has been disclosed in many patents over decades, only little academic literature is available. The success of the process over various catalysts has been claimed in many of these patents. However, further studies are still required to ascertain the actual reaction mechanism, mitigating carbon deposition and catalyst deactivation, and the role of different catalysts to optimize the reaction desired products. The current research work evaluates the potential of CrOx/Al2O3, K-CrOx/Al2O3, Pt/Al2O3 and K-Pt/Al2O3 to investigate the trans-hydrogenation of the pentane (P)/1-hexyne (1HY) system, the pentane (P)/1,5-hexadiene (1,5-HD) system and the pentane (P)/2,4-Hexadiene (2,4-HD) system over a range temperatures (523-773 K). The fresh catalysts were first characterised by N2 adsorption using the BET method, X-ray diffraction, Raman spectroscopy, Thermogravimetric analysis, Temperature programme oxidation (TPO), Temperature programmed reduction (TPR), Electron paramagnetic resonance (EPR), Atomic absorption spectroscopy (AAS) and colorimetric analysis. The Free energy (ΔG) for the reaction of pentane with 1-hexyne, 1,5-hexadiene and 2,4-hexadiene shows that trans-hydrogenation is thermodynamically favoured at most temperatures for the reaction of pentane with 1-hexyne, however this is not always the case when hexadienes are the hydrogen acceptors. When 2,4-HD is the acceptor, ΔG is +ve at all the reaction temperatures tested. When pentane or hexyne/hexadiene or a 5:1 mixture was passed over the catalyst, in the temperature range of 523K -773 K, it was found that trans-hydrogenation process had taken place but many of the products are alkylated olefinic and alkylated hydrocarbons. Regarding all systems previously mentioned above, the ratio of olefin to alkylated olefin products was ~50:50 at 773K, however, this ratio was found to vary at other temperatures. The lowest ratio of ~10:90 was obtained at 523K. Dissociation of the hydrocarbon reactant was also observed leading to production of cracked products such as CH4, C2H4 and subsequent formation of a carbonaceous overlayer on the catalyst surface. This was not the case with the 2,4-hexadiene reactant, the trans-hydrogenation is poor, as expected from the free energies. The trans-hydrogenation process was shown to improve the conversion of pentane when co-fed with the hexyne to ~26% and to ~90% when co-fed with 1,5HD using the chromia catalyst at 773K, both values are much higher than the equilibrium conversion of the pentane dehydrogenation. Higher conversions of the pentane were subsequently obtained with other catalysts, but the chromia/alumina and K-CrOx/Al2O3 catalyst exhibits greater trans-hydrogenation activity. With the 2,4HD acceptor, very low conversions of pentane were obtained with all the catalysts: in general conversions lower than when the pentane was run alone were obtained. The products observed were unique for each catalyst. However, it was observed that for each catalyst, only the distribution of the products changed with temperature. This also accounted for changes in both the cracking products and the carbon laydown on the catalyst. The deactivation regeneration cycles shows very similar conversion of both reactants. There is a small deactivation observed for the longer time run; however these were not very significant. It was observed that some of the major products were consumed with time, but are used for the formation of other major products. However, this is more prominent with pentane/hexyne run using the CrOx/Al2O3 catalyst.
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Bragg, Sarah E. "Cyclopentadienone Conversions to Terephthalates and Cycloadditions of Alkynes and Azides." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1306971571.
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Okada, Takumi. "Studies on Ruthenium Complex-Catalyzed Functionalization of Alkenes and Alkynes." 京都大学 (Kyoto University), 2002. http://hdl.handle.net/2433/149811.
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Tokimizu, Yusuke. "Synthesis of Heterocyclic Scaffolds through Transition-Metal-CatalyzedCascade Reactions of Alkynes." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199500.
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Peter, Sebastian. "Oxyfunctionalization of alkanes, alkenes and alkynes by unspecific peroxygenase (EC 1.11.2.1)." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-113321.
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Unspecific peroxygenase (EC 1.11.2.1) represents a group of secreted hemethiolate proteins that are capable of catalyzing the selective mono-oxygenation of diverse organic compounds using only H2O2 as a cosubstrate. In this study, the peroxygenase from Agrocybe aegerita (AaeUPO) was found to catalyze the hydroxylation of various linear (e.g n-hexane), branched (e.g. 2,3-dimethylbutane) and cyclic alkanes (e.g. cyclohexane). The size of n-alkane substrates converted by AaeUPO ranged from gaseous propane (C3) to n-hexadecane (C16). They were mono-hydroxylated mainly at the C2 and C3 position, rather than at the terminal carbon, and the corresponding ketones were formed as a result of overoxidation. In addition, a number of alkenes were epoxidized by AaeUPO, including linear terminal (e.g. 1-heptene), branched (2-methyl-2-butene) and cyclic alkenes (e.g. cyclopentene), as well as linear and cyclic dienes (buta-1,3-diene, cyclohexa-1,4-diene). Furthermore, the conversion of terminal alkynes (e.g. 1- octyne) gave the corresponding 1-alkyn-3-ol in low yield. Some of the reactions proceeded with complete regioselectivity and - in the case of linear alkanes, terminal linear alkenes and alkynes - with moderate to high stereoselectivity. The conversion of n-octane gave (R)-3-octanol with 99% enantiomeric excess (ee) and the preponderance of the (S)-enantiomer reached up to 72% ee of the epoxide product for the conversion of 1-heptene. Catalytic efficiencies (kcat/ Km) determined for the hydroxylation and respectively epoxidation of the model compounds cyclohexane and 2-methyl-2-butene were 2.0 × 103 M-1 s-1 and 2.5 × 105 M−1 s−1. The results obtained in the deuterium isotope effect experiment with semideuterated n-hexane and the radical clock experiment with norcarane clearly demonstrated that the hydroxylation of alkanes proceeds via hydrogen abstraction, the formation of a substrate radical and a subsequent oxygen rebound mechanism. Moreover, stopped-flow experiments and substrate kinetics proved the involvement of a porphyrin radical cation species (compound I; AaeUPO-I) as reactive intermediate in the catalytic cycle of AaeUPO, similar to other hemethiolate enzymes (e.g. cytochrome P450 monooxygenases, P450s)Die Gruppe der Unspezifischen Peroxygenasen (EC 1.11.2.1) umfasst extrazelluläre Häm-Thiolat-Enzyme, die mittels H2O2 als Cosubstrat die selektive Monooxygenierung unterschiedlicher organischer Verbindungen katalysieren. In der vorliegenden Arbeit konnte gezeigt werden, dass die von Agrocybe aegerita sekretierte Peroxygenase (AaeUPO) verschiedene lineare (z. B. n-Hexan), verzweigte (z. B. 2,3-Dimethylbutan) und zyklische Alkane (z. B. Cyclohexan) hydroxyliert. Die Größe der von der AaeUPO umgesetzten Substrate reichte vom gasförmigen Propan (C3) bis hin zu n-Hexadekan (C16). Die Alkane wurden bevorzugt am zweiten und dritten Kohlenstoffatom (C2 und C3) hydroxyliert; eine Hydroxylierung am terminalen Kohlenstoff konnte nur vereinzelt und in geringem Umfang beobachtet werden. Die Überoxidationen der primär gebildeten, sekundären Alkohole führte außerdem zur Entstehung der entsprechenden Ketonderivate. Darüber hinaus wurde eine Vielzahl linearer terminaler (z. B. 1-Hepten), verzweigter (z. B. 2-Methyl-2-Buten) und zyklischer Alkene (z. B. Cyclopenten) sowie linearer und zyklischer Diene (1,3-Butadien, 1,4-Cyclohexadien) durch die AaeUPO epoxidiert. Die Umsetzung terminaler Alkine (z. B. 1-Octin) führte zur Entstehung der jeweiligen 1-Alkin-3-ole. Manche dieser Reaktionen verliefen ausgeprägt regioselektiv und, im Falle der linearen Alkane sowie der linearen terminalen Alkene und Alkine, mit mittlerer bis hoher Stereoselektivität. So ergab beispielsweise die Umsetzung von n-Octan einen Enantiomerenüberschuss größer 99% für (R)-3-Octanol; die Epoxidierung von 1-Hepten lieferte einen Enatiomeerenüberschuss (ee) von bis zu 72% für das (S)-Enantiomer. Die katalytischen Effizienzen, die für die Hydroxylierung bzw. Epoxidierung der Modellverbindungen Cyclohexan und 2-Methyl-2-Buten ermittelt wurden, betragen 2.0 × 103 M-1 s-1 und 2.5 × 105 M−1 s−1. Der ausgeprägte Deuterium-Isotopen-Effekt, der im Zuge der Umsetzung von semideuteriertem n-Hexan beobachtet wurde sowie die Ergebnisse des Radical-Clock-Experiments mit Norcarane als Substrat bestätigten, dass die Hydroxylierung von Alkanen über Wasserstoffabstraktion, die Bildung eines Substratradikals und anschließende direkte Sauerstoffrückbindung verläuft. Die Stopped-Flow-Experimente belegen zudem das Auftreten eines Porphyrin-Kationradikal-Intermediates (Compound I; AaeUPO-I) im katalytischen Zyklus der AaeUPO (vergleichbar mit dem reaktiven Intermediat der P450-Monooxygenasen)
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Fosu, Stacy C. "Functionalization of Arenes, Amines, Alkenes, and Alkynes Mediated by Radical Pathways." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555514456659022.
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Jurberg, Igor Dias. "Synthesis of Alkynes and New Transformations Catalyzed by Gold(I) Complexes." Palaiseau, Ecole polytechnique, 2010. http://pastel.archives-ouvertes.fr/docs/00/57/00/64/PDF/These_Igor.pdf.
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Sur la plateforme de thèses en ligne Tel on trouve le résumé suivant en français : La synthèse d'alcynes en utilisant des isoxazolones comme précurseurs a été une méthode développée dans notre laboratoire dans ler dernières années. Nous avons appliqué cette méthodologie pour la synthèse de 3-alkynylamides et leur utilisation pour générer des dihydropyrrolones. Nous avons aussi développé de nouvelles réactions catalysées pour complexes d'or(I): la synthèse de 4-oxazol-2-ones à partir de Boc-ynamides, une séquence de transfert 1,5 d'hydrure et cyclisation pour former des éther cycliques et la formation de dérivés de cinnolines. Nous avons aussi développé un étude mecanistique concernant l'effet de deux contre-ions usuellement utilisés dans la cycloisomérization de 1,6-enynes catalysée à l'or: le NTf2 et SbF6. L'influence de groupes loin de la partie alcène a aussi été remarquée et étudiée en plus grand détail. Également, une première investigation vers l'identification d'un catalyseur permettant l'accès à des cycles à 6-chaînons a été réalisée (Ce qui est le résultat moins souvent observé pour ce type de réaction, où le cycle à 5-chaînons est généralement obtenu)Ur la plateforme de thèses en ligne Tel on trouve le résumé suivant en anglais : The synthesis of alkynes using isoxazolones as precursors has been one of the methods studied by our laboratory in the last years. We have applied this methodology in the synthesis of 3-alkynylamides and their use to generate dihydropyrrolones. We have also developped new reactions catalyzed by Gold(I) complexes: the synthesis of 4-oxazol-2-ones from Boc-ynamides, a 1,5hydride/cyclization sequence affording carbocyclic ether structures and the formation of cinnoline derivatives. We have also developped a mechanistic study concerning the effect of two common counter-ions employed in gold-mediated cycloisomerization of 1,6-enynes: NTf2 and SbF6. The remote influence of the substituent on the alkene moiety was identified and studied in more detail. In the same way, a first investigation towards the identification of a catalyst allowing access to 6-membered cycles was performed (This outcome is less frequently observed, as 5-membered rings are usually obtained in these processes)
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MARSICANO, VINCENZO. "Functionalised alkynes as starting materials to build up valuable organic scaffolds." Doctoral thesis, Università degli Studi dell'Aquila, 2021. http://hdl.handle.net/11697/169731.
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The synthesis of organic compounds is of great interest nowadays, primarily because of their application in multiple fields, even in everyday life. A major concern, however, is the impact that organic synthetic methodologies may have on both environment and human health. Because of this, great effort has been devoted to the development of novel efficient synthetic strategies, with the concept of efficiency shifting from the only consideration of the overall yield to a much more complex definition, including also waste production, energy requirements, toxicity and hazard of chemicals used.
Alkynes are emerging as interesting building blocks in organic synthesis, thanks to their versatility and the ability to act as both nucleophiles and electrophiles, upon activation by Brønsted and Lewis acids. Moreover, the presence of proximal functional groups, such as carbonyl, amino and hydroxy groups, allows alkynes to undergo cascade one-pot reaction to generate complex organic architectures.
The present PhD work is centred on the use of alkynes, in particular nitrogen-containing alkynes, to access valuable organic scaffolds, using efficient synthetic strategies such as multi-bond forming reactions, microwave-assisted organic synthesis and transition-metal catalysis. Four different types of alkyne-containing substrates (2-alkynylanilines, β-(2-aminophenyl)-α,β-ynones, propargylamines and ynamides) have been successfully employed in the synthesis of valuable organic compounds that are expected to have potential applications in medicinal chemistry, material sciences or as intermediates in the synthesis of more complex organic compounds. Moreover, the synthesis of ten new potential TRPM8 antagonists has been carried out in collaboration with Dompé Farmaceutici S.p.A.; the project focused on the design of new phenyl thiazole derivatives and on the planning of the synthetic sequences to obtain them, with a particular attention on the improvement of already-planned strategies, especially in terms of reduction of wastes and sources of potential contamination of the final product. Moreover, the introduction of an alkyne moiety in the thiazole core enabled to access interesting new isocoumarin analogues.
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Chan, Wing-kei. "Oxidation of alkenes and alkynes catalyzed by a cyclodextrin-modified ketoester and metalloporphyrins." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36709591.
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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.