Enantioselective Nucleophile-catalyzed Cycloadditions PDF Download
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Author: Jonathan E. Wilson (Ph. D.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 345
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Book Description
Chapter 1 describes the development of an asymmetric nucleophile-catalyzed [2+2] cycloaddition of ketenes with aldehydes. This is the first report of a catalytic enantioselective synthesis of trisubstituted [beta]-lactones. Two enantioselective phosphine-catalyzed [3+2] cycloadditions of allenoates are detailed in Chapter 2. A method for the asymmetric synthesis of cyclopentenes via a [3+2] cycloaddition of allenoates with enones is first discussed. This is followed by a report of our efforts to extend this [3+2] methodology to imine electrophiles. We conclude, in Chapter 3, with an account of the development of a novel phosphine-catalyzed synthesis of bicyclo[3.3.0]octanones and bicyclo[4.3.0]nonanones. Preliminary results for an enantioselective variant of this method are also disclosed.
Author: Jonathan E. Wilson (Ph. D.)
Publisher:
ISBN:
Category :
Languages : en
Pages : 345
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Book Description
Chapter 1 describes the development of an asymmetric nucleophile-catalyzed [2+2] cycloaddition of ketenes with aldehydes. This is the first report of a catalytic enantioselective synthesis of trisubstituted [beta]-lactones. Two enantioselective phosphine-catalyzed [3+2] cycloadditions of allenoates are detailed in Chapter 2. A method for the asymmetric synthesis of cyclopentenes via a [3+2] cycloaddition of allenoates with enones is first discussed. This is followed by a report of our efforts to extend this [3+2] methodology to imine electrophiles. We conclude, in Chapter 3, with an account of the development of a novel phosphine-catalyzed synthesis of bicyclo[3.3.0]octanones and bicyclo[4.3.0]nonanones. Preliminary results for an enantioselective variant of this method are also disclosed.
Author: Olga Garcia-Mancheno
Publisher: John Wiley & Sons
ISBN: 3527348573
Category : Technology & Engineering
Languages : en
Pages : 418
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Book Description
Explores the potential of new types of anion-binding catalysts to solve challenging synthetic problems Anion-Binding Catalysis introduces readers to the use of anion-binding processes in catalytic chemical activation, exploring how this approach can contribute to the future design of novel synthetic transformations. Featuring contributions by world-renowned scientists in the field, this authoritative volume describes the structure, properties, and catalytic applications of anions as well as synthetic applications and practical analytical methods. In-depth chapters are organized by type of catalyst rather than reaction type, providing readers with an accessible overview of the existing classes of effective catalysts. The authors discuss the use of halogens as counteranions, the combination of (thio)urea and squaramide-based anion-binding with other types of organocatalysis, anion-binding catalysis by pnictogen and tetrel bonding, nucleophilic co-catalysis, anion-binding catalysis by pnictogen and tetrel bonding, and more. Helping readers appreciate and evaluate the potential of anion-binding catalysis, this timely book: Illustrates the historical development, activation mode, and importance of anion-binding in chemical catalysis Explains the analytic methods used to determine the anion-binding affinity of the catalysts Describes catalytic and synthetic applications of common NH- and OH-based hydrogen-donor catalysts as well as C-H triazole/triazolium catalysts Covers amino-catalysis involving enamine, dienamine, or iminium activation approaches Discusses new trends in the field of anion-binding catalysis, such as the combination of anion-binding with other types of catalysis Presenting the current state of the field as well as the synthetic potential of anion-binding catalysis in future, Anion-Binding Catalysis is essential reading for researchers in both academia and industry involved in organic synthesis, homogeneous catalysis, and pharmaceutical chemistry.
Author: Vittorio Caprio
Publisher: John Wiley & Sons
ISBN: 1405190914
Category : Science
Languages : en
Pages : 409
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Book Description
Asymmetric synthesis has become a major aspect of modern organic chemistry. The stereochemical properties of an organic compound are often essential to its bioactivity, and the need for stereochemically pure pharmaceutical products is a key example of the importance of stereochemical control in organic synthesis. However, achieving high levels of stereoselectivity in the synthesis of complex natural products represents a considerable intellectual and practical challenge for chemists. Written from a synthetic organic chemistry perspective, this text provides a practical overview of the field, illustrating a wide range of transformations that can be achieved. The book captures the latest advances in asymmetric catalysis with emphasis placed on non-enzymatic methods. Topics covered include: Reduction of alkenes, ketones and imines Nucleophilic addition to carbonyl compounds Catalytic carbon-carbon bond forming reactions Catalytic reactions involving metal carbenoids Conjugate addition reactions Catalysis in Asymmetric Synthesis bridges the gap between undergraduate and advanced level textbooks and provides a convenient point of entry to the primary literature for the experienced synthetic organic chemist.
Author: Montserrat Diéguez
Publisher: John Wiley & Sons
ISBN: 3527804072
Category : Technology & Engineering
Languages : en
Pages : 431
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Book Description
An important reference for researchers in the field of metal-enzyme hybrid catalysis Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a comprehensive review of the most current strategies, developed over recent decades, for the design, synthesis, and optimization of these hybrid catalysts as well as material about their application. The contributors—noted experts in the field—present information on the preparation, characterization, and optimization of artificial metalloenzymes in a timely and authoritative manner. The authors present a thorough examination of this interesting new platform for catalysis that combines the excellent selective recognition/binding properties of enzymes with transition metal catalysts. The text includes information on the various applications of metal-enzyme hybrid catalysts for novel reactions, offers insights into the latest advances in the field, and contains an informative perspective on the future: Explores the development of artificial metalloenzymes, the modern and strongly evolving research field on the verge of industrial application Contains a comprehensive reference to the research area of metal-enzyme hybrid catalysis that has experienced tremendous growth in recent years Includes contributions from leading researchers in the field Shows how this new catalysis combines the selective recognition/binding properties of enzymes with transition metal catalysts Written for catalytic chemists, bioinorganic chemists, biochemists, and organic chemists, Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a unique reference to the fundamentals, concepts, applications, and the most recent developments for more efficient and sustainable synthesis.
Author:
Publisher:
ISBN:
Category : Beta lactamases
Languages : en
Pages : 276
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Book Description
This study focused on asymmetric synthesis of biologically important molecules [beta]-lactones or [beta]-lactams through a formal [2+2] cycloaddition of ketenes and aldehydes or imines, and hydrogenation reaction on ketene heterodimers leading to dipropionate and deoxypropionate derivatives. 31P NMR was utilized as a tool for mechanistic studies of the new phosphine catalyzed [2+2] reactions. We firstly developed the method of a BINAPHANE-catalyzed formal [2+2]-cycloadition of disubstituted ketenes and inexpensive N-tosyl arylimines that provides access to a variety of highly substituted [beta]-lactams (16 examples). The BINAPHANE catalytic system displays moderate to excellent enantioselectivity (up to 98% ee) and high diastereoselectivity in most cases, favoring formation of the trans-diastereomer (13 examples with dr [greater than or equal to] 90:10). We then extended the substrate scope for the methodology of chiral phosphine-catalyzed formal [2+2] cycloaddition of aldehydes and ketoketenes, to achiral aldehydes (both aromatic and aliphatic) and alkylarylketenes or dialkylketenes. A preference for formation of the trans diastereomer was observed in these reactions. Evidence for the involvement of phosphonium enolate intermediates in the reaction mechanism was obtained by monitoring the 31P NMR spectrum and by comparison of these results with previously characterized intermediates observed in the phosphine-catalyzed ketene homodimerization reaction. We then extended this methodology further to the diastereoselective synthesis of [beta]-lactones bearing two or three stereogenic centers, from disubstituted ketenes and [alpha]- or [beta]-chiral aldehydes. Tri-n-butylphosphine was found to be the optimal nucleophilic catalyst in terms of effecting both good yield (up to 79%) and diastereoselectivy (dr[greater than or equal to]3:1 for 8 examples, up to 10:1) in [beta]-lactone formation. We lastly developed a stereodivergent and diastereoselective procedure to access dipropionate and deoxypropionate derivatives through Pd/C-catalyzed hydrogenation or hyrogenolysis of enantioenriched ketene heterodimers. Catalytic hydrogenation of the E-isomer of ketene heterodimer [beta]-lactones provides access to syn, anti-[beta]-lactones (dipropionate derivatives) bearing three stereogenic centers (dr up to 19:1), while catalytic hydrogenolysis of the Z-isomer of ketene heterodimers facilitates access to anti-deoxypropionate derivatives (dr up to 13:1). Mechanistic analysis suggest that [beta]syn-elimination from a hydropalladated intermediate is a key step in the formation of the deoxypropionate derivatives.
Author: Albrecht Berkessel
Publisher: John Wiley & Sons
ISBN: 3527604057
Category : Science
Languages : en
Pages : 454
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Book Description
Asymmetric catalysis represents still one of the major challenges in modern organic chemistry. Besides the well-established asymmetric metal-complex-catalysed syntheses and biocatalysis, the use of "pure" organic catalysts turned out to be an additional efficient tool for the synthesis of chiral building blocks. In this handbook, the experienced authors from academia and industry provide the first overview of the important use of such metal-free organic catalysts in organic chemistry. With its comprehensive description of numerous reaction types, e.g., nucleophilic substitution and addition reactions as well as cycloadditions and redox reactions, this book targets organic chemists working in industry and academia, and deserves a place in every laboratory.
Author: Rainer Mahrwald
Publisher: Springer Science & Business Media
ISBN: 9048138655
Category : Science
Languages : en
Pages : 333
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Book Description
Organocatalyzed Reactions I and II presents a timely summary of organocatalysed reactions including: a) Enantioselective C-C bond formation processes e.g. Michael-addition, Mannich-reaction, Hydrocyanation (Strecker-reaction), aldol reaction, allylation, cycloadditions, aza-Diels-Alder reactions, benzoin condensation, Stetter reaction, conjugative Umpolung, asymmetric Friedel-Crafts reactions; b) Asymmetric enantioselective reduction processes e.g. Reductive amination of aldehydes or ketones, asymmetric transfer hydrogenation; c) Asymmetric enantioselective oxidation processes; d) Asymmetric epoxidation, Bayer-Villiger oxidation; e) Enantioselective a-functionalization; f) A-alkylation of ketones, a-halogenation and a-oxidation of carbonyl compounds.
Author: Peter I. Dalko
Publisher: John Wiley & Sons
ISBN: 3527658882
Category : Science
Languages : en
Pages : 1499
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Book Description
Structured in three parts this manual recollects efficient organocatalytic transformations around clear principles that meet actual standard in asymmetric synthesis. Chapters were written by acknowledged leaders of the organocatalysis field, and are presented in a concise way. Volume 1: Privileged Catalysts gives insight to readers to the continuously increasing variety of catalysts, and the relatively complex interactions that make organocatalytic reactions selective. An appendix recollects catalyst structures with the adequate cross-references. Volume 2: Activations covers the fundamental activation types (non-covalent and covalent activations) and helps understanding the importance of physical parameters, and in particular, the role of water, that influences reactivity and selectivity. Volume 3: Reactions and Applications highlights transformations by reaction types. The final part of this volume is dedicated to application in multistep synthesis and industrial applications. Considering the ever increasing interest in the organocatalysis field, the book aims addressing to a large audience: to academic, and, industrial researchers, students and teachers who are interested in synthetic organic chemistry at advanced level. This book provides non-specialists with an introduction to the topic as well as serving as a valuable source for newcomers and researchers searching for an up-to-date and comprehensive overview of this promising area of synthetic organic chemistry.
Author: Kengadarane Anebouselvy
Publisher: Royal Society of Chemistry
ISBN: 1782620907
Category : Science
Languages : en
Pages : 220
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Book Description
In the last decade a new era in asymmetric catalysis has been realised by the discovery of L-proline induced chiral enamines from carbonyls. Inspired by this, researchers have developed many other primary catalytic species in situ, more recently secondary catalytic species such as aminals have been identified for use in asymmetric synthesis. High-yielding asymmetric synthesis of bioactive and natural products through mild catalysis is an efficient approach in reaction engineering. In the early days, synthetic chemists mainly focused on the synthesis of complex molecules, with less attention on the reaction efficiency and eco-friendly conditions. Recent investigations have been directed towards the development of atom economy, eco-friendly and enantioselective synthesis for more targeted and efficient synthesis. Building on the momentum of this rapidly expanding research area, Dienamine catalysis for organic synthesis will provide a comprehensive introduction, from the preformed species, in situ generation and onto their applications in the synthesis of bioactive molecules and natural products.
Author: Uli Kazmaier
Publisher: Springer Science & Business Media
ISBN: 3642227481
Category : Science
Languages : en
Pages : 354
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Book Description
Giovanni Poli, Guillaume Prestat, Frédéric Liron, Claire Kammerer-Pentier: Selectivity in Palladium Catalyzed Allylic Substitution.- Jonatan Kleimark and Per-Ola Norrby: Computational Insights into Palladium-mediated Allylic Substitution Reactions.- Ludovic Milhau, Patrick J. Guiry: Palladium-catalyzed enantioselective allylic substitution.- Wen-Bo Liu, Ji-Bao Xia, Shu-Li You: Iridium-Catalyzed Asymmetric Allylic Substitutions.- Christina Moberg: Molybdenum- and Tungsten-Catalyzed Enantioselective Allylic Substitutions.- Jean-Baptiste Langlois, Alexandre Alexakis: Copper-catalyzed enantioselective allylic substitution.- Jeanne-Marie Begouin, Johannes E. M. N. Klein, Daniel Weickmann, B. Plietker: Allylic Substitutions Catalyzed by Miscellaneous Metals.- Barry M. Trost, Matthew L. Crawley: Enantioselective Allylic Substitutions in Natural Product Synthesis.
