Density functional theory calculations have been used to investigate catalytic mechanism of polymer formation containing polar groups, from the synthesis of the monomer to the synthesis of the macromolecule. In the spirit of a sustainable and green chemistry, we initially focused attention on the coupling of CO2 as economically convenient and recyclable C1 source with C2H4 to form acrylate and/or butirro-lactone, two important polar monomers. In this process formation of a mettallolactone via oxidative coupling of CO2 and C2H4 is an important intermediate. Given this background, we explored in detail (chapter-3) several Ni based catalysts for CO2 coupling with C2H4 to form acrylate. In this thesis we report on the competitive reaction mechanisms (inner vs outer sphere) for the oxidative coupling of CO2 and ethylene for a set of 11 Ni-based complexes containing bisphosphine ligands. In another effort, considering incorporation of a C=C bond into a metal-oxygen-Functional-Group moiety is a challenging step in several polymerization reactions, we explored the details of this reaction (chapter4) using two different catalysts that are capable to perform this reaction in the synthesis of heterocycles. Specifically, the [Rh]-catalyzed intramolecular alkoxyacylation ([Rh] = [RhI(dppp)+] (dppp, 1,3-Bis-diphenylphosphino-propane), and the [Pd]/BPh3 intramolecular alkoxyfunctionalizations. Rest of the thesis we worked on understanding the details of the polymerization of polar monomers using organocatalysts based on N-heterocyclic carbenes (NHC) or N-heterocyclic olefins (NHO). In particular (chapter-5) we studied the polymerization of N-methyl N-carboxy- anhydrides, towards cyclic poly(N-substituted glycine)s, promoted by NHC catalysts. In good agreement with the experimental findings, we demonstrated that NHC promoted ring opening polymerization of N-Me N-Carboxyanhydrides may proceed via two different catalytic pathways. In a similar effort we studied polymerization of propylene oxide (PO) (chapter-6) promoted by N-heterocyclic olefins (NHO) in combination with benzylic alcohol (BnOH). Calculations support the experimental observation that there might be two different catalytic pathways namely the anionic and the zwitterionic pathways. Potential energy surfaces analysis suggested in different NHO one or other mechanism is operational which is strongly depends on steric and electronic properties of particular NHO taken in account.

No description available.

Usage of Flavinium Salts as Catalysts of Oxidation Reactions Summary This diploma thesis deals with use of flavinium salts as a catalysts of oxidation reactions. 3,7,8,10-tetramethylisoalloxazin 25, 5-ethyl-3,7,8,10-tetramethylisoalloxazinium perchlorate 16 and 5-ethyl-1,3-dimethylalloxazinium perchlorate 26 had been prepared. Salts 16, 26 and other previously prepared phlavinium salt 28 were tested as potential catalysts for the oxidation of phenylboronic acids to the corresponding phenols, and especially for the use of oxygen as the oxidizing agent. The best solvent systems were found through testing and followed possible influence of the substituent on the phenyl ring of boronic acid was investigated. This initial screening can be used as a basis for further and more detailed testing of catalytic efficiency of flavinium salts and to study the oxidation mechanism.

This thesis presents the development of new acyl anion precursors and their applications. The main concern of this thesis was to make use of acyl anion precursors in catalytic bond forming reactions. Toward this aim, previously known cyanide ion catalyzed cleavage of benzils was investigated in scope and efficiency in unsymmetrical benzoin condensation. Although benzils were proved to be useful entities as acyl anion precursors in benzoin condensation, they suffer some major drawbacks. Therefore acylphosphonates were proposed and investigated as a new generation of acyl anion precursor. They were found to be highly versatile and efficient in both catalytic unsymmetrical benzoin synthesis and other useful transformations.

This diploma thesis deals with the stereoselective addition reaction of benzothiophenone derivatives to ketimines derived from isatin using bifunctional organocatalysis. The stereoselective addition reaction was optimized to provide the appropriate reaction conditions which were subsequently used to study the scope of the reaction. Keywords Organocatalysis, stereoselective synthesis, bifunctional organocatalysts, ketimines, sulphur heterocykles.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21275号 / 工博第4503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 杉野目 道紀, 教授 村上 正浩, 教授 松原 誠二郎 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Le but de notre projet était de mettre au point un procédé éco-compatible d’organocatalyse asymétrique hétérogène en flux continu. Pour réaliser ce procédé, nous avons choisi d’utiliser la cupréine, un alcaloïde dérivé de la quinine comme organocatalyseur bifonctionnel. La silice (un matériau inorganique mésoporeux) a été choisie comme support pour l’hétérogénéisation du catalyseur. La cupréine immobilisée sur silice a ensuite été testée comme organocatalyseur de la réaction d’addition de Michael asymétrique entre le trans-β-nitrostyrène (accepteur de Michael) et le diméthyl malonate (donneur de Michael) en condition de flux continu.Nous avons tout d’abord immobilisé la cupréine sur deux types de silice selon trois stratégies différentes. Chaque stratégie nous a permis d’obtenir le support greffé avec des quantités de cupréine allant de 0,2 à 0,4 mmol par gramme de silice, ainsi que des silices greffées possédant des caractéristiques différentes selon les stratégies envisagées.L’évaluation de l’activité catalytique de la cupréine greffée sur silice a ensuite été réalisée en milieu hétérogène en batch. Différents solvants biosourcés ont alors été testés comme solvants alternatifs pour la réaction d’addition de Michael. Le 2-MeTHF s’est révélé être un bon solvant et a été choisi pour les expériences de catalyse en flux continu. Les résultats obtenus en catalyse avec la cupréine greffée sur silice sont comparables à ceux en milieu homogène (excès énantiomériques supérieur ou égale à 85 % et conversion supérieure à 96 %) exceptés pour la fréquence de rotation (TOF, mol de substrat converti/mol de catalyseur/durée de réaction) qui est trois fois plus faible en milieu hétérogène (0,2 h-1 pour 0,6 h-1 en milieu homogène).Enfin, cette réaction d’addition de Michael a été réalisée en flux continu avec les différentes silices greffées. La fréquence de rotation de la cupréine a été multipliée par deux (0,4 h-1) et le nombre de rotation (TON, mol de substrat converti/mol de catalyseur) a lui aussi été augmenté, passant de 16 en milieu hétérogène en batch à 63 en condition de flux continu. Finalement, différents dérivés du trans-β-nitrostyrène (Chloré, phénolique et méthoxy en position 4) ont été testés avec succès.Ainsi, à notre connaissance, nous avons réalisé la première réaction d’addition de Michael entre le trans-β-nitrostyrène et le diméthyl malonate, organocatalysée en milieu hétérogène en batch et en flux continu par la cupréine immobilisée sur silice, en utilisant un solvant biosourcé. Nous avons réussi à mettre au point le procédé de catalyse hétérogène en flux continu permettant de recycler facilement le catalyseur et aussi d’augmenter la productivité de la cupréine immobilisée par rapport au milieu hétérogène en batch, tout en conservant une conversion et une énantiosélectivité équivalente à celles en milieu homogène. / The aim of our project was to develop an eco-friendly process based on heterogeneous asymmetric organocataysis in continuous flow conditions. To succeed in this development, we chose to use a quinine-derived bifunctional organocatalyst: cupreine. Silica, a mesoporous inorganic material, was chosen as the support to immobilize this organocatalyst. The grafted cupreine was then tested as catalyst for the asymmetric Michael addition between the trans-β-nitrostyrene (Michael acceptor) and the dimethyl malonate (Michael donor) in continuous flow condition.First, we immobilized the catalyst on two types of silica, following three different strategies. The various cupreine-grafted silicas we obtained were functionnalized with 0.2 to 0.4 mmol of cuprein per gram of silica. Each one of them possessed specific characteristics depending of the followed strategy.The assessment of the catalytic activity of immobilized silica was then performed in batch condition. Different bio-based solvents were used for the Michael addition. 2-MeTHF was chosen as the best solvent among those tested and used in continuous flow. Immobilized cupreine proved to be as efficient in heterogenous condition as in homogenous (enantiomeric excess was superior or equal to 85 % and conversion better than 96 %), except for turn over frequency (TOF, mol of converted substrate/mol of catalyst/reaction time) which is three times lower in hetereogeneous condition (0.2h-1 to 0.6 h-1 in homogenous condition).Michael addition of trans-β-nitrostyrene to dimethyl malonate was then realized in continuous flow condition, using the various silica-supported catalysts. Turn over frequency of cupreine was doubled (0.4 h-1) and the turn over number (mol of converted substrate/mol of catalyst) increased from 16 to 63 in continuous flow condition. Derivatives of trans-β-nitrostyrene (chlorinated, phenolic and methoxylated in position 4) were successfully tested in continuous flow.To the best of our knowledge, we realized the first asymmetric Michael addition between trans-β-nitrostyrene and the dimethyl malonate, catalysed by silica-supported cupreine in batch and in continuous flow, using a bio-based solvent.We successfully developed an eco-friendly process based on heterogeneous organocatalysis in continuous flow. This process favorited an efficient recycling of the supported catalyst, and increased the productivity of grafted cupreine compare to the heterogeneous condition in batch. The enantioselectivity of the cupreine for this reaction was similar in both homogeneous and heterogeneous conditions.

No description available.

La synthèse asymétrique organo-catalysée est un domaine de recherche en pleine expansion visant une chimie plus verte. Nous nous sommes intéressés au développement d’une réaction de Michael asymétrique organocatalysée en mettant à profit la catalyse par liaison hydrogène et l’activation énamine afin de contrôler en une seule étape la formation d’adduits portant un centre carboné quaternaire à partir de cétones non activées. Ainsi, nous avons développé des organocatalyseurs bifonctionnels de type squaramide qui ont permis d’obtenir les adduits de Michael attendu à partir de cycloalcanones alpha-substituées avec une bonne énantiosélectivité et une grande régiosélectivité dans un processus sous micro-ondes et sans solvant. Nous avons développé de nouveaux systèmes catalytiques sur la base du motif squaramide qui sont simples, efficaces et opérationnels. Nous avons étudié également l'utilité de nos systèmes organocatalytiques dans d'autres transformations comme la polymérisation verte. Afin de réduire l'utilisation de métaux toxiques pour produire des polymères bien définis sans trace de métaux et d'importance environnementale ou médicale, nous avons également étudié comment nos organo-catalyseurs de type squaramide pourraient contrôler la polymérisation verte par ouverture de cycle. Les systèmes organocatalytiques basés sur des squaramides étaient également applicables à la polymerisation par ouverture de cycle afin de donner des polylactides de dispersité étroite et de masses moléculaires contrôlées. / Organocatalyzed asymmetric synthesis is a growing and rapidly expanding research field for a greener chemistry. In this respect, we were interested in developing an organocatalyzed asymmetric Michael reaction taking advantage of H-bond catalysis and enamine activation allowing control of quaternary carbon center from unactivated ketones. Hence compared with well-known H-bond donor urea and thiourea organocatalysts, we first propose bifunctional squaramide organocatalysts for the one-pot transformation of unsymmetrical ketones to produce Michael adducts exhibiting a stereocontrolled quaternary carbon center in a neat microwave process. We also developped new catalytic systems based on the squaramide motive that are efficient and operationnaly simple, and produce Michael adducts in a good regioselectivity with an excellent enantio-selectivity. We also studied the usefulness of our systems in other transformations like green polymerization. In order to reduce the use of toxic metals to produce metal-free and well-defined polymers of environmental and medical significance, we also studied how our squaramide organocatalysts could control the green ring opening polymerization (ROP.The squaramide organocatalyst-based systems were also applicable to ROP to give polylactides of narrow dispersity and controlled molecular masses.