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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Iridium-Catalyzed Carbon-Carbon Bond Formation Reactions via C-H Bond Activation / イリジウム触媒によるC-H結合活性化を経るC-C結合形成反応

Ebe, Yusuke 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20192号 / 理博第4277号 / 新制||理||1615(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 依光 英樹, 教授 丸岡 啓二, 講師 西村 貴洋 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
12

Development of New C-C Bond Forming Reactions Utilizing Light as Energy Source / 光をエネルギー源とする新規炭素―炭素結合形成反応の開発

Masuda, Yuusuke 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20409号 / 工博第4346号 / 新制||工||1674(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 村上 正浩, 教授 吉田 潤一, 教授 杉野目 道紀 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
13

Avaliação da promiscuidade catalítica de soroalbuminas em sínteses orgânicas / Evaluation of catalytic promiscuity of serum albumins in organic synthesis

Santana, Ana Carolina de Toledo [UNESP] 26 February 2016 (has links)
Submitted by ANA CAROLINA DE TOLEDO SANTANA null (actoledo@iq.unesp.br) on 2016-03-17T17:25:32Z No. of bitstreams: 1 Dissertação Carol Final.pdf: 7825510 bytes, checksum: 921c29706ed56e5ef489712bae28fc30 (MD5) / Approved for entry into archive by Juliano Benedito Ferreira (julianoferreira@reitoria.unesp.br) on 2016-03-21T20:10:04Z (GMT) No. of bitstreams: 1 santana_act_me_iq_par.pdf: 4512361 bytes, checksum: 07a7dc911b2bdd27db8608948a16848b (MD5) / Made available in DSpace on 2016-03-21T20:10:04Z (GMT). No. of bitstreams: 1 santana_act_me_iq_par.pdf: 4512361 bytes, checksum: 07a7dc911b2bdd27db8608948a16848b (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho teve como principal objetivo estudar a atividade catalítica de soroalbumina bovina (BSA) em reações formadoras de uma nova ligação C-C: Reações aldólica, de Henry e Morita-Baylis-Hillman (MBH). Em todos os casos a BSA atuou como catalisador, visto que quando as reações foram realizadas sem sua presença, não houve formação dos produtos desejados. Os rendimentos obtidos para as reações aldólica (37%), Henry (80%) e MBH (73%), variaram de bons a moderados e não foi observada enantiosseletividade para nenhuma das reações estudadas. As soroalbuminas são proteínas que formam muita emulsão dificultando os processos downstream na separação dos produtos e materiais de partida. Visando minimizar este inconveniente, a BSA foi submetida à imobilização em MCLEA (magnetic cross-linking enzyme aggregates) utilizando nanopartículas magnéticas de óxido de ferro. Nestes casos, o biocatalisador pôde ser facilmente retirado do meio reacional com aplicação de um campo magnético externo. Esta metodologia afetou diretamente no rendimento da reação de Henry, passando de 80% para 89%. Porém, para as outras reações a melhoria no rendimento não foi tão expressiva. A imobilização também não foi eficaz para o aumento dos excessos enantioméricos. Até o momento para a reação de MBH com os substratos utilizados, não há relatos na literatura para a síntese do aduto desejado catalisado pela BSA. Sendo assim, optamos por realizar um planejamento fatorial completo dessa reação visando otimizar as condições reacionais bem como os rendimentos. As variáveis estudadas foram: temperatura, concentração do biocatalisador e condição do biocatalisador (livre ou imobilizado). Os resultados obtidos mostraram que a variável com maior influência na reação, é a concentração do biocatalisador. A conversão obtida passou de 30% para 40% utilizando 2,2 μmol de BSA. Em seguida, realizamos um estudo de ascendência da concentração do catalisador visando otimizar este parâmetro. A conversão obtida passou para 73% quando foram utilizadas 3,7 μmol de biocatalisador imobilizado. Realizamos um estudo de reciclagem do biocatalisador imobilizado. Foi possível reutiliza-lo porém com diminuição da conversão a partir do segundo ciclo. Os resultados obtidos nesta dissertação evidenciam o potencial biocatalítico da BSA em reações para a formação de ligação C-C. / This work aimed to study the catalytic activity of bovine serum albumin (BSA) in reactions that form a new C-C bond: aldol reactions, Henry and Morita-Baylis-Hillman (MBH). In all cases BSA served as the catalyst, whereas when the reactions were carried out without their presence there was no formation of the desired products. The yields obtained for aldol reactions (37%), Henry (80%) and MBH (73%), ranged from good to moderate enantioselectivity and was not observed for any of the studied reactions. The serum albumins are proteins that form the much emulsion difficulting downstream processes in separation of the products and starting materials. To minimize this inconvenience, the BSA was subjected to immobilization in M-CLEA (magnetic cross-linking enzyme aggregates) using magnetic nanoparticles of iron oxide. In these cases the biocatalyst could be easily removed from the reaction medium by applying an external magnetic field. This methodology directly affect the yield of the Henry reaction, from 80% to 89%. However, for other reactions the improvement of yields was less pronounced. The immobilization was also not effective for improving the enantiomeric excess. So far for the MBH reaction with the worked substrates, there are no reports in the literature for the synthesis of the desired adduct catalyzed by BSA. So we decided to study a full factorial design of this reaction to optimize the reaction conditions and yields. The variables studied were: temperature, the biocatalyst concentration and biocatalyst conditions (free and immobilized). The concentration of biocatalyst was the major factor with interference in all reactions. The conversion increased from 30% to 40% using 2.2 μmol of BSA. Then we perform a study of catalyst concentration to optimize this parameter. The conversion increased to 73% when they were used 3.7 μmol immobilized biocatalyst. To evaluate the retention of catalytic activity of BSA immobilized, it was performed a study of the immobilized biocatalyst recycling. It was possible the reuse but with reduced conversion from the second cycle. The results obtained in this work demonstrated the potential of BSA in C-C bond formation reactions.
14

New Ring-opening Reactions of Four-membered Carbo- and Sila-cyclic Compounds and Synthesis of 2-Alkoxy-1、3-dienes from Propargylic Alcohol Derivatives / 炭素及びケイ素からなる四員環化合物の新規開環反応及びプロパルギルアルコール誘導体からの2-アルコキシ- 1 , 3-ジエンの合成

Okumura, Shintaro 23 May 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21274号 / 工博第4502号 / 新制||工||1700(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 村上 正浩, 教授 松原 誠二郎, 教授 杉野目 道紀 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
15

Nouveaux iodanes chiraux pour des réactions asymétriques sans métal : développements méthodologiques pour la création de liaisons carbone–carbone / New chiral iodanes for metal-free asymmetric alkynylation reactions : methodological developments for carbon-carbon bond creation

Companys, Simon 15 December 2016 (has links)
La chimie des composés à base d'iode hypervalent (i.e., iodanes) connaît un fort intérêt depuis le début des années 1990 comme en témoigne le panel de composés iodés disponibles commercialement et le nombre de transformations chimiques que ces réactifs peuvent promouvoir. Au cours de la dernière décennie,les recherches se sont essentiellement concentrées sur le développement d’iodanes chiraux et leurs applications en synthèse asymétrique. La plupart de ces iodanes sont utilisés pour la création hautement sélective de liaison carbone-hétéroatome (C–O, C–N, C–F…). La création asymétrique de liaison carbone-carbone (C–C) médiée par des iodanes chiraux a cependant été très peu étudiée jusqu'à présent. Dans ce contexte, notre groupe de recherche a décrit la synthèse de nouveaux iodanes-λ5chiraux biaryliques et de type Salen ainsi que leurs applications à la désaromatisation oxygénante asymétrique de 2-alkyl phénols avec des excès énantiomériques (ee) supérieurs à 90%. Ces travaux de thèse sont consacrés au développement de nouveaux iodanes-λ3 chiraux porteurs de ligands carbonés transférables pour la création asymétrique sans métal de liaison C–C. Sont plus particulièrement décrits la synthèse de bis(alcynyl-iodanes-λ3) biphényliques atropopurs et leur utilisation dans l’alcynylation énantiosélective de β-cétoesters (jusqu’à 68% ee) et, pour la première fois, de naphtols (jusqu’à 84% ee). / The chemistry of hypervalent organoiodine compounds (i.e., iodanes) has unarguably experienced an impressive development since the early 1990s, as evidenced by both the diversity of iodane reagents that are commercially available today and the number of chemical transformations that those reagents can promote.Over the last decade, the elaboration of new chiral iodanes and their applications in asymmetric synthesis have attracted special interests and research efforts. Most ofthem are involved in highly selective carbon-heteroatom bond-forming reactions (C–O, C–N, C–F…). However, C–C bond-forming reactions in a stereoselective fashion with chiral iodane are yet underexploited. In this context, our research group reported the synthesis of new biarylic and Salen-type chiral λ5‐iodanes and their successful application to the asymmetric hydroxylative phenol dearomatization of 2alkylphenols, with enantiomeric excesses (ee) above 90%. This thesis work is dedicated to the development of new chiral λ3‐iodanes bearing transferable carbon-basedligands for metal‐free asymmetric C–C bond construction. In particular, the synthesis of chiral biphenylic bis(alkynyl-λ3-iodanes) and their successful application to the enantioselective alkynylation of β‐ketoesters (up to 68% ee) and 2‐substituted naphthols (up to 84% ee) are described.
16

Metalls de transició en la formació d'enllaços carboni-carboni: cicloaddicions [2+2+2] catalitzades per Rh(I) i acoblaments creuats catalitzats per Pd(0) i Ni(0)

Brun Massó, Sandra 27 April 2012 (has links)
Carbon-carbon bond formation reactions catalyzed by transition metals represent one of the most versatile and efficient strategies in organic synthesis. The catalytic transformations contribute to the development of methodologies that are more environmentally benign and with high atomic economy. Despite the progress in this field in recent years, the development of new and more efficient strategies of synthesis continues to be one of the main challenges of organic chemistry. In the present PhD thesis the Rh(I)-catalyzed [2+2+2] cycloaddition reaction of different macrocyclic and acyclic substrates containing double and/or triple bond in their structure are studied. On the other hand, Matsuda-Heck reactions and Suzuki-Miyaura cross-couplings using diazonium salts as electrophiles under Pd(II) catalysis with mild reaction conditions and a totally aqueous medium have been studied. Palladium-catalyzed carbon-carbon bonds a good alternative both in terms of cost and activity is the use of nickel catalysts. Finally, new Ni(0) complexes with macrocyclic and open-chain ligands containing double and triple bonds have been synthesized and completely characterized. Their activity in Suzuki cross-coupling reactions is then studied. / Les reaccions de formació d’enllaços carboni-carboni catalitzades per metalls de transició representen una de les estratègies més versàtils i eficients en síntesi orgànica. Les transformacions catalítiques contribueixen al desenvolupament de metodologies més benignes amb el mediambient i proporcionen una elevada economia atòmica. Encara que siguin molts els avenços fets en aquest camp en els últims anys, el desenvolupament de noves i més eficients estratègies de síntesi segueixen essent un dels reptes principals de la química orgànica. En la present tesi s'ha estudiat la reacció de cicloaddició [2+2+2] catalitzada per Rh(I) de diferents substrats macrocíclics i acíclics contenint dobles i/o triples enllaços. Per altra banda, s’han portat a terme reaccions de Matsuda-Heck i acoblaments creuats de Suzuki-Miyaura utilitzant sals de diazoni com a electròfils sota catàlisi per Pd(II) emprant condicions suaus de reacció i en medi totalment aquós. Una bona alternativa al pal•ladi en termes econòmics i d’activitat és l’ús de catalitzadors de níquel. Finalment s’han sintetitzat i caracteritzat estructuralment nous complexos de Ni(0) amb lligands macrocíclics i de cadena oberta contenint diferents insaturacions i s'ha estudiat la seva activitat catalítica en reaccions de Suzuki.
17

Development of New Carbon-Carbon Bond-Forming Strategies: Formation and Reactivity of sp³-gem-Organodimetallic Palladium(II)/MRn Alkane Intermediates (MRn=Dialkylalumino, Trialkylstannyl)

Trepanier, Vincent Hector Emile 07 November 2006 (has links)
Investigation of the catalytic formation, reactivity and synthetic scope of sp³-gem-organodimetallic palladio(II)/main group metal (main group metal = tributylstannyl, dialkylalumino) alkane species has been carried out. Insight was expanded regarding the inter- and intramolecular reactivity of vinylmetallic reagents in presence of transition metal catalysts. New Pd-catalysed methodologies for carbon-carbon bond formation were developed, such as cyclopropanation of strained olefins, as well as tandem vinylalane arylation/1,2-methyl transfer and 1,2-diarylation. On the one hand, geminal π-allylpalladio(II)/tributylstannylalkane intermediates are produced by oxidative addition of Pd(0) catalysts to α-tributylstannylpropenyl acetate derivatives. They adopt ambiphilic behaviour depending on the transition metal pre-catalyst, presence or absence of phosphine ligands, and reaction temperature. In presence of tetrakis(triphenylphosphine)palladium(0) with additional bidentate ligand, the carbenoid reactivity of these gem-organobismetallic species is exposed by reaction with dimethyl malonate. Deuterium-labeling studies demonstrated sequential functionalisation of the C-Sn and C-Pd bonds. Conversely, phosphine-free catalyst bis(dibenzylideneacetone)palladium(0) uncovers metal-carbene reactivity, and dimerisation and strained alkene cyclopropanation reactions are observed. The nature of the palladium catalyst controls the reactivity of the carbenoid species. Finally, bis(cyclooctadienerhodium(I) chloride) catalytically activates the alkenylstannane moiety, leaving the allylic acetate leaving group available for further transformations. On the other hand, gem-disubstituted trifluoromethanesulfonyloxy- and iodopalladio(II)/ dialkylaluminoneopentane species are generated by intramolecular migratory insertion of 2,2-disubstituted-1-butenyldialkylalanes with σ-arylpalladium(II) triflate and iodide intermediates. Using excess Lewis-basic 1,4-diazabicyclo[2.2.2]octane, electron-rich tris(para-methoxyphenyl)phosphine ligand and acetonitrile as solvent, tandem arylation/1,2-alkyl migration from aluminum to carbon affords 7-substituted-1-ethyl-1-methylindanes containing an all-carbon quaternary stereogenic centre in good yields. This reaction is tolerant of 6-aryl methyl ethers, thioethers and trimethylsilanes. Deuterium labeling established that protiodealumination of the key neopentyl(methyl)aluminum triflate intermediate is caused by the acetonitrile solvent. The organodimetallic species in that study were shown to be configurationally stable, hence the stereospecificity of the process that proceeds via carbopalladation, transmetalation and reductive elimination of an alkylpalladium(II) intermediate. When applied to 1-naphthyl triflate-tethered vinylalanes, the same reaction conditions mediate stereospecific 1,2-diarylation, leading to 2,3,3a,4-tetrahydro-1H-cyclopenta[def]phenanthrenes in excellent yields. The influence of DABCO, tether length and solvent polarity was studied. Selective tandem arylation/1,2-methyl migration could also be achieved in non-polar solvent in absence of Lewis base. While steric properties took precedence over electronic considerations when inducing product selection, preagostic C-H···Pd interactions were postulated to facilitate 1,3-metal migration in the production of 1H-cyclopenta[def]phenanthrene derivatives.
18

Development of New Carbon-Carbon Bond-Forming Strategies: Formation and Reactivity of sp³-gem-Organodimetallic Palladium(II)/MRn Alkane Intermediates (MRn=Dialkylalumino, Trialkylstannyl)

Trepanier, Vincent Hector Emile 07 November 2006 (has links)
Investigation of the catalytic formation, reactivity and synthetic scope of sp³-gem-organodimetallic palladio(II)/main group metal (main group metal = tributylstannyl, dialkylalumino) alkane species has been carried out. Insight was expanded regarding the inter- and intramolecular reactivity of vinylmetallic reagents in presence of transition metal catalysts. New Pd-catalysed methodologies for carbon-carbon bond formation were developed, such as cyclopropanation of strained olefins, as well as tandem vinylalane arylation/1,2-methyl transfer and 1,2-diarylation. On the one hand, geminal π-allylpalladio(II)/tributylstannylalkane intermediates are produced by oxidative addition of Pd(0) catalysts to α-tributylstannylpropenyl acetate derivatives. They adopt ambiphilic behaviour depending on the transition metal pre-catalyst, presence or absence of phosphine ligands, and reaction temperature. In presence of tetrakis(triphenylphosphine)palladium(0) with additional bidentate ligand, the carbenoid reactivity of these gem-organobismetallic species is exposed by reaction with dimethyl malonate. Deuterium-labeling studies demonstrated sequential functionalisation of the C-Sn and C-Pd bonds. Conversely, phosphine-free catalyst bis(dibenzylideneacetone)palladium(0) uncovers metal-carbene reactivity, and dimerisation and strained alkene cyclopropanation reactions are observed. The nature of the palladium catalyst controls the reactivity of the carbenoid species. Finally, bis(cyclooctadienerhodium(I) chloride) catalytically activates the alkenylstannane moiety, leaving the allylic acetate leaving group available for further transformations. On the other hand, gem-disubstituted trifluoromethanesulfonyloxy- and iodopalladio(II)/ dialkylaluminoneopentane species are generated by intramolecular migratory insertion of 2,2-disubstituted-1-butenyldialkylalanes with σ-arylpalladium(II) triflate and iodide intermediates. Using excess Lewis-basic 1,4-diazabicyclo[2.2.2]octane, electron-rich tris(para-methoxyphenyl)phosphine ligand and acetonitrile as solvent, tandem arylation/1,2-alkyl migration from aluminum to carbon affords 7-substituted-1-ethyl-1-methylindanes containing an all-carbon quaternary stereogenic centre in good yields. This reaction is tolerant of 6-aryl methyl ethers, thioethers and trimethylsilanes. Deuterium labeling established that protiodealumination of the key neopentyl(methyl)aluminum triflate intermediate is caused by the acetonitrile solvent. The organodimetallic species in that study were shown to be configurationally stable, hence the stereospecificity of the process that proceeds via carbopalladation, transmetalation and reductive elimination of an alkylpalladium(II) intermediate. When applied to 1-naphthyl triflate-tethered vinylalanes, the same reaction conditions mediate stereospecific 1,2-diarylation, leading to 2,3,3a,4-tetrahydro-1H-cyclopenta[def]phenanthrenes in excellent yields. The influence of DABCO, tether length and solvent polarity was studied. Selective tandem arylation/1,2-methyl migration could also be achieved in non-polar solvent in absence of Lewis base. While steric properties took precedence over electronic considerations when inducing product selection, preagostic C-H···Pd interactions were postulated to facilitate 1,3-metal migration in the production of 1H-cyclopenta[def]phenanthrene derivatives.
19

Studies towards Developing Diastereoselective SN1 Reactions of α-Keto Carbocations

Dubland, Joshua 06 April 2010 (has links)
Although α-keto carbocations have been demonstrated to be viable intermediates in solvolysis reactions, their applications in synthesis are scarce. These species can be considered to be equivalent to “reversed polarity” enolates and, as such, could be useful for the asymmetric formation of carbon-carbon and carbon-heteroatom bonds. In principle, facial selectivity in additions to α-keto carbocations may be induced using easily removed ester, amide, or imide chiral auxiliaries. Efforts to achieve such diastereoselective SN1 reactions of α-keto carbocations are described herein.
20

Studies towards Developing Diastereoselective SN1 Reactions of α-Keto Carbocations

Dubland, Joshua 06 April 2010 (has links)
Although α-keto carbocations have been demonstrated to be viable intermediates in solvolysis reactions, their applications in synthesis are scarce. These species can be considered to be equivalent to “reversed polarity” enolates and, as such, could be useful for the asymmetric formation of carbon-carbon and carbon-heteroatom bonds. In principle, facial selectivity in additions to α-keto carbocations may be induced using easily removed ester, amide, or imide chiral auxiliaries. Efforts to achieve such diastereoselective SN1 reactions of α-keto carbocations are described herein.

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