Download or read book Development and Evaluation of Chiral Catalysts for Asymetric C C and C H Bond Forming Reactions written by Christian Ebner and published by . This book was released on 2012 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development and Evaluation of Chiral Catalysts for Asymmetric C C and C H Bond forming Reactions written by Christian Ebner and published by Cuvillier Verlag. This book was released on 2012-03-05 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work was dedicated to the development and evaluation of new chiral catalysts for asymmetric C-C and C-H bond forming reactions. In the first part of the thesis an ESI-MS screening method is described, which allows the determination of a chiral catalyst´s selectivity in the palladium catalyzed asymmetric allylic alkylation by testing its racemic form. The value of this new method was demonstrated when different new aryl-PHOX-type ligands, which are not easily accessible in their enantiopure form, were evaluated. In the second part new PHOX-type ligands were tested in the iridium-catalyzed asymmetric hydrogenation of different unsaturated compounds. Although low activities and selectivities were found in most cases, one ligand showed promising results in the hydrogenation of allylic alcohols and imines. Furthermore air- and moisture-stable secondary phosphine oxide (SPO) containing bidentate ligands were tested in the palladium-catalyzed asymmetric allylic alkylation reaction. SPO,N-ligands bearing a PHOX type backbone were inactive in this transformation as they tend to form inactive palladium-bis-ligand complexes. SPO,P ligands however, were able to promote the desired reaction in a highly selective fashion although only low activities were found. During this work as well a new organo-catalyst, based on the structure of 2,3-dihydrobenzo[1,4]oxazine, was developed which allows for the asymmetric organo-catalyzed transfer-hydrogenation of α,β-unsaturated aldehydes. This catalyst was able to reduce for the first time β, β-diaryl acrylaldehydes with very good activities and high enantioselectivities. Moreover an ESI-MS based mechanistic study on the tripeptide catalyzed conjugate addition reaction of aldehydes to nitroolefins was carried out. By this all reaction intermediates postulated for an enamine mechanism have been detected. Furthermore the attack of the enamine onto the nitroolefin was found to be the selectivity determining step in this process. The last part of this work aimed for the asymmetric α -allylation of carbonyl compounds by a tandem-catalysis approach. An intensive screening of both the organo-catalyst and the palladium-ligand led to reaction conditions which allowed for the selective mono-allylation of ketones in high yields. The formation of a quaternary center by α -allylation of α -branched aldehydes was also achieved. However, only low enantiomeric excesses were obtained in this transformation for the different catalyst systems tested.

Download or read book Enantioselective C C Bond Forming Reactions written by and published by Elsevier. This book was released on 2023-12-01 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enantioselective C-C Bond Forming Reactions: From Metal Complex-, Organo-, and Bio-catalyzed Perspectives, Volume 73 in the Advances in Catalysis series, highlights new advances in the field, with this new volume presenting interesting chapters on topics such as An introduction to Chirality, Metal-catalyzed stereoselective C-C-bond forming reactions, Enantioselective C-C bond forming reactions promoted by organocatalysts based on unnatural amino acid derivatives, Enantioselective C-C bond formation in complex multicatalytic system, Gold-based multicatalytic systems for enantioselective C-C Bond forming reactions, Novel enzymatic tools for C-C bond formation through the development of new-to-nature biocatalysis, and more. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in Advances in Catalysis serials Updated release includes the latest information in the field

Download or read book Asymmetric C C Bond Formation with Chiral Catalysts written by Menapara Tusharkumar and published by Alibaba. This book was released on 2023-05-25 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book "Asymmetric C-C Bond Formation with Chiral Catalysts" by Menapara Tusharkumar explores the fascinating field of asymmetric catalysis for carbon-carbon bond formation reactions. The book emphasizes on the use of chiral catalysts for the synthesis of enantiopure compounds that are critical for the development of new drugs, agrochemicals, and materials. The use of chiral catalysts offers high enantioselectivity and stereoselectivity, and therefore, provides an efficient way for the synthesis of organic compounds with desired stereochemistry. The book covers the design and synthesis of chiral catalysts, including ligands and transition metal complexes. The author discusses the chemical properties of chiral catalysts and their influence on the reaction mechanisms and stereoselectivity. The book also highlights the importance of molecular recognition in asymmetric catalysis and its application in various catalytic reactions. The book covers various types of asymmetric catalysis, including organocatalysis, metal-catalyzed reactions, and enzymatic catalysis. It discusses the advantages and limitations of each type of catalysis and provides examples of their applications in organic synthesis. The author also emphasizes the importance of green chemistry and sustainability in asymmetric catalysis. The book covers a range of topics related to asymmetric C-C bond formation, including diastereoselectivity, substrate specificity, kinetic resolution, and stereochemical control. The book also provides examples of the synthesis of natural products, alkene coupling, palladium-catalyzed cross-coupling reactions, oxidative coupling reactions, Diels-Alder reactions, and Michael addition reactions using chiral catalysts. Overall, "Asymmetric C-C Bond Formation with Chiral Catalysts" is an essential reference for organic chemists, catalysis researchers, and students who are interested in asymmetric catalysis, enantioselective synthesis, and stereochemistry. The book provides a comprehensive overview of the field, including recent advances and challenges, and offers practical guidance for the design and optimization of chiral catalysts for asymmetric C-C bond formation reactions.

Download or read book Catalyzed Mizoroki Heck Reaction or C H activation written by Sabine Berteina-Raboin and published by MDPI. This book was released on 2020-02-13 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last few decades, research on the elaboration by palladium-catalytic processes of C-C bonds or the activation of C–H bonds has increased considerably. Yet there is still room for much improvement in terms of selectivity, or enantioselectivity, via the development of new ligands or the study of the catalytic effect of other metals to carry out the same chemical transformations. In addition, the attention paid to environmentally friendly methods in terms of the quantities of catalysts, ligands, and solvents is currently indispensable. The Mizoroki-Heck reaction is one of these important catalytic methods which generates C-C bonds in organic synthesis and is also possible by C-H activation. This book, titled “Catalyzed Mizoroki-Heck Reaction or C-H activation” focuses on new advances in the formation of C-C bonds or new C-H activation methods. It contains original research papers and short reviews on the synthesis of biologically active compounds using these catalytic processes, the identification of new catalysts, of new conditions allowing selectivity or enantioselectivity, the activity and stability of catalyst under turnover conditions, and all improvements in catalytic processes.

Download or read book Asymmetric Catalysis of Carbon carbon Bond Forming Reactions written by Souvagya Biswas and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nature has established numerous methods for synthesis of complex molecules utilizing simple and abundant resources such as the use of CO2, H2O and N2 using sunlight as a source of energy. Even more impressive are the high chemo-, regio-, and stereoselectivites observed in these transformations with a wide variety of both prochiral and chiral substrates. However, methods for the enantioselective incorporation of feedstock materials such as CO, HCN, CO2 or simple alkenes into prochiral molecules are limited and remain an important challenge in the field. The hydrovinylation reaction (HV), where ethylene is added across a carbon-carbon double bond, has been known for nearly fifty years, starting with the works of Hata, Alderson and Wilke. During the past few years, through an approach that relied mostly on mechanistic insights and systematic examination of ligand effects, our group discovered a number of protocols for Ni(II)- and Co(II)-catalyzed enantioselective hydrovinylation (HV) reactions of vinylarenes, 1,3-dienes and strained olefins. While the Ni(II)-catalyzed hydrovinylation (HV) reaction is one of the most selective asymmetric catalyzed carbon-carbon bond forming reactions, its use has been limited to alkenes conjugated to an aromatic ring and strained alkenes. We recently found Co(II)-bisphosphine complexes show much improved regioselectivity with broader functional group compatibility in 1,3-dienes. By utilizing finely tuned catalysts derived from Co(II)-bisphosphine complexes and Me3Al or methylaluminoxane (MAO) acyclic (E) and (Z)-1,3-dienes were found to undergo efficient hydrovinylation giving mostly 1,4-hydrovinylation products in an atmosphere of ethylene. In order to expand the hydrovinylation chemistry, we turned our attention to one of the mostly widely used intermediates on organic chemistry, viz., silyl enol ethers. Trialkylsilyl enol ethers are exceptionally versatile intermediates often used as enolate surrogates for the synthesis of carbonyl compounds. Yet there are no reports of broadly applicable, catalytic methods for the synthesis of chiral silyl enol ethers carrying latent functionalities useful for synthetic operations beyond the many possible reactions of the enol ether moiety itself. The work presented herein reports a general procedure for highly catalytic (substrate : catalyst ratio up to 1000:1) and enantioselective (96% to 98% major enantiomer) synthesis of silyl enol ethers bearing a vinyl group at a chiral carbon at the beta-position. The reactions, run under ambient conditions, use trialkylsiloxy-1,3-dienes and ethylene (1 atmosphere) as precursors, and readily available (bis-phosphine)-cobalt(II) complexes as catalysts. Once we have established the HV reaction conditions of the siloxydienes, we turn our attention towards diastereoselective functionalization of the hydrovinylated products. Under optimized conditions, we are able to successfully utilize our 1,4-hydrovinylated products as reactive nucleophilic synthons for several electrophilic reactions keeping moderate to good diastereomeric ratios. The silyl enolates can be readily converted into novel enantiopure vinyl triflates, a class of highly versatile cross-coupling reagents, enabling the syntheses of other enantiomerically pure trisubstituted alkene intermediates not easily accessible by current methods.

Download or read book Handbook of Asymmetric Heterogeneous Catalysis written by Kuiling Ding and published by John Wiley & Sons. This book was released on 2008-09-08 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this most up-to-date handbook each chapter contains a general introduction, followed by the principles of the immobilization and, finally, applications. In this way, it covers the most important approaches currently employed for the heterogenization of chiral catalysts, including data tables, applications, reaction types and literature citations. For chemists in both academia and industry as well as those working in the fine chemical and pharmaceutical industry.

Download or read book Asymmetric Catalysis from a Chinese Perspective written by Shengming Ma and published by Springer Science & Business Media. This book was released on 2011-07-06 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Qi-Lin Zhou and Jian-Hua Xie: Chiral Spiro Catalysts.- Fuk Loi Lam, Fuk Yee Kwong and Albert S. C. Chan: Chiral Phosphorus Ligands with Interesting Properties and Practical Applications.- Jiang Pan, Hui-Lei Yu, Jian-He Xu, Guo-Qiang Lin: Advances in Biocatalysis: Enzymatic Reactions and Their Applications.- Mei-Xiang Wang: Enantioselective Biotransformations of Nitriles.- Man Kin Wong, Yiu Chung Yip and Dan Yang: Asymmetric Epoxidation Catalyzed by Chiral Ketones.- W. J. Liu, N. Li and L. Z. Gong: Asymmetric Organocatalysis.- Qing-Hua Fan and Kuiling Ding: Enantioselective Catalysis with Structurally Tunable Immobilized Catalysts.- Chang-Hua Ding, Xue-Long Hou: Transition Metal-Catalyzed Asymmetric Allylation.- Jian Zhou and Yong Tang: Enantioselective Reactions with Trisoxazolines.- Xiang-Ping Hu, Duo-Sheng Wang, Chang-Bin Yu, Yong-Gui Zhou, and Zhuo Zheng: Adventure in Asymmetric Hydrogenation: Synthesis of Chiral Phosphorus Ligands and Asymmetric Hydrogenation of Heteroaromtics.

Download or read book Asymmetric Catalysis of Carbon carbon Bond Forming Reactions Through Hydrogen Bonding written by Vijaya Bhasker Gondi and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Metal Catalysed Carbon Carbon Bond Forming Reactions written by Stanley M. Roberts and published by John Wiley & Sons. This book was released on 2005-01-28 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: The chemist has a vast range of high-tech catalysts to use when working in fine chemical synthesis but the catalysts are generally hard to use and require both time, skill and experience to handle properly. The Catalysts for Fine Chemical Synthesis series contains tested and validated procedures which provide a unique range resources for chemists who work in organic chemistry. "... of great value to synthetic organic chemists..." (The Chemists, Summer 2003) Volume 3 in the series focuses on catalysts for carbon-carbon bond formation and presents practical and detailed protocols on how to use sophisticated catalysts by the "inventors" and "developers" who created them. The combination of protocols and review commentaries helps the reader to easily and quickly understand and use the new high-tech catalysts.

Download or read book Synthesis and Application of New Chiral Peptides Guanidines and Formamides as Organocatalysts for Asymmetric C C Bond Formation Reactions written by Sunil Jagtap and published by . This book was released on 2006 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cooperative Catalysis written by René Peters and published by John Wiley & Sons. This book was released on 2015-04-27 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by experts in the field, this is a much-needed overview of the rapidly emerging field of cooperative catalysis. The authors focus on the design and development of novel high-performance catalysts for applications in organic synthesis (particularly asymmetric synthesis), covering a broad range of topics, from the latest progress in Lewis acid / Br?nsted base catalysis to e.g. metal-assisted organo catalysis, cooperative metal/enzyme catalysis, and cooperative catalysis in polymerization reactions and on solid surfaces. The chapters are classified according to the type of cooperating activating groups, and describe in detail the different strategies of cooperative activation, highlighting their respective advantages and pitfalls. As a result, readers will learn about the different concepts of cooperative catalysis, their corresponding modes of operation and their applications, thus helping to find a solution to a specific synthetic catalysis problem.

Download or read book Sustainable and Cost effective Development of Chiral Metal catalysts for C H and C X Bond Forming Reactions written by Carlota Borràs Noguera and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'obtenció de compostos enantiomèricament purs ha esdevingut una necessitat que ha conduit a un important progrés en la catàlisi asimètrica, principalment usant compostos organometàl·lics quirals. Entre les diferents estratègies en l'optimització dels catal·litzadors per aconseguir elevades selectivitats i activitats, el disseny i correcta selecció de lligands quirals, modificant-ne les seves propietats és fonamental i la més utilitzada. Que un lligand sigui fàcil de sintetitzar a partir de compostos de partida accessibles i que aquests lligands siguin estables i fàcils de manipular, tenen un elevat interès en la industria. En aquest context, el principal objectiu d'aquesta tesi és la síntesi de diferents famílies de lligands quirals, acomplint els requisits prèviament esmentats, i la seva posterior aplicació a diverses reaccions asimètriques d'elevat interès industrial: hidrogenació d'olefines funcionalitzades i no funcionalitzades catalitzada per Rh i Ir, hidrogenació de cetones catalitzada per Ir, reaccions de substitució al·lílica catalitzades per Pd i reaccions de substitució propargílica catalitzada per Cu. S'han sintetitzat diverses famílies fosfit/fosfinit-tioèter/selenoèter, carbè-tioèter, amino-fosfit/fosfinit/fosfina, i varies famílies de lligands tridentats.

Download or read book Catalytic Asymmetric Carbon carbon Bond Forming Reactions and Synthesis written by Sha Lou and published by . This book was released on 2008 with total page 678 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Organozinc Derivatives and Transition Metal Catalysts written by Janine Cossy and published by Walter de Gruyter GmbH & Co KG. This book was released on 2023-05-22 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organozinc reagents are less reactive than Grignard reagents but they are much more chemoselective. Since the Negishi cross-coupling reaction developed by Ei-ichi Negishi, who was awarded the Nobel Price in chemistry in 2010, a number of cross-coupling reactions involving organozinc derivatives and transition metal catalysts (Pd, Ni, Fe, Co, Cu, ...) has been tuned up to form C-C bonds. This book on "Organozinc derivatives and transition metal catalysts" has been written by experts in the field and is a complement to the book entitled "Grignard reagents and transition metal catalysts" (a De Gruyter book, edited by J. Cossy). Grignard reagents or organozinc reagents, that is the question? From a given substrate, what is the best organometallic reagent and the best transition metal to form a C-C bond by using a cross-coupling reaction? The solution might be found in these two books.

Download or read book Improved Synthesis and Application of Planar chiral Nucleophilic Catalysts in Asymmetric Reactions and Copper catalyzed Enantioselective N H Insertion Reactions written by Elaine C. Lee and published by . This book was released on 2007 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of an improved synthesis of nucleophilic planar-chiral catalysts is described in Chapter 1. This route is amenable to scale-up and preparative chiral HPLC is unnecessary to resolve the racemic catalysts. Using planar-chiral catalysts, two synthetic methodology projects have been developed: Chapter 2 describes the first asymmetric synthesis of trans P-lactams, and Chapter 3 describes the asymmetric synthesis of tertiary a-chloroesters. In the chapter describing the asymmetric synthesis of trans [beta]-lactams, we present mechanistic data supporting a novel mechanism, in which the N-triflylimine, rather than the ketene, reacts with the catalyst first. In the chapter describing the asymmetric synthesis of tertiary a-chloroesters, we introduced an under-utilized commercially available chlorinating reagent (2,2,6,6-tetrachlorocyclohexanone). Finally, in chapter 4, the Cu-catalyzed asymmetric synthesis of [alpha]-aminoesters via an N-H insertion is described. We have demonstrated that carbamates such as BocNH2 and CbzNH2 are efficient coupling partners in reactions with a-diazoesters to generate highly useful Boc- or Cbz-protected a-aminoesters.

Download or read book Catalyst Components for Coupling Reactions written by Gary A. Molander and published by John Wiley & Sons. This book was released on 2013-05-30 with total page 1749 pages. Available in PDF, EPUB and Kindle. Book excerpt: The long awaited Handbook for all synthetic chemists working on coupling reactions, compiling all major catalyst components in use in the area. Consists of a compilation of articles taken from the EROS database, with the inclusion of about 20 newly commissioned catalysts/pre-catalysts/ligands that have made an impact in this area of synthetic organic chemistry. Includes catalyst systems used in Heck, Kumada-Tamao-Corriu, Suzuki-Miyaura, Hiyama-Hatanaka, Negishi, Migita-Kosugi-Stille, Buchwald-Hartwig, and Tsuji-Trost coupling reactions.