Download or read book Planar Chiral Hydrogen Bond Donor Catalysts written by Jakob Schneider and published by Cuvillier Verlag. This book was released on 2010-11-02 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on the first synthesis and application of planar-chiral [2.2]paracyclophane- derived hydrogen-bond donor catalysts, thereby inducing a unique chiral motif into the emerging field of thiourea organocatalysis. Reaction acceleration through hydrogen-bond catalysis has made a significant impact on the field, rendering the development of potent catalyst structures extremely valuable. Based on the [2.2]paracyclophane scaffold, mono- and bi-functional thiourea catalysts were prepared. The rigidity of the [2.2]paracyclophane structure leads to a unique setup of the substituents. In pseudo-geminal position to the thiourea moiety, a hydroxy group was selected and introduced as the second functionality. In a 12-step synthesis, the enantiopure hydroxy- substituted [2.2]paracyclophanylene thiourea was obtained. Furthermore, efficient access to enantiopure pseudo-geminally substituted 13-amino-4- bromo[2.2]paracyclophane was developed. The aminobromide was employed in cross- coupling reactions to yield arylated amino[2.2]paracyclophanes, exhibiting a broad range of electronic and steric features useful for organocatalytic applications. The developed catalysts were applied in asymmetric organic transformations and proved most useful in the transfer hydrogenation reaction. The hydroxy-substituted thiourea catalyst particularly exhibited catalytic activity and stereoselectivity. To shed light on the mode of action of this class of hydrogen-bond catalysts, various analytic methods were conducted. Through extensive crystallographic and NMR complexation experiments, the binding properties of the catalysts were investigated in terms of their interaction with hydrogen-bond- accepting functional groups. Furthermore, quantum chemical DFT and ab initio calculations were undertaken to explore the favored conformations of [2.2]paracyclophane-derived thioureas. The combined findings revealed substrate-dependent activation via single or double hydrogen bonding between the NH groups of the thiourea and the respective substrate. Furthermore, a class of readily accessible hydrogen-bond thiourea catalysts was developed, derived from amino acids. Their steric and electronic features were modulated by their degree of substitution at the carbinol carbon center. All catalysts were applied in the asymmetric transfer hydrogenation of nitroolefins, furnishing the products in up to 99% yield and 87% enantiomeric excess.
Download or read book Planar Chiral Hydrogen Bond Donor Catalysts written by Jakob Schneider and published by . This book was released on 2010 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Planar Chiral 2 2 Paracyclophanediols as Metal free Hydrogen bonding Organocatalysts written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Enantioselective Organocatalysis written by Peter I. Dalko and published by John Wiley & Sons. This book was released on 2013-08-14 with total page 1499 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Organic Chemistry of Enzyme Catalyzed Reactions Revised Edition written by Richard B. Silverman and published by Elsevier. This book was released on 2002-03-07 with total page 736 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Organic Chemistry of Enzyme-Catalyzed Reactions is not a book on enzymes, but rather a book on the general mechanisms involved in chemical reactions involving enzymes. An enzyme is a protein molecule in a plant or animal that causes specific reactions without itself being permanently altered or destroyed. This is a revised edition of a very successful book, which appeals to both academic and industrial markets. Illustrates the organic mechanism associated with each enzyme-catalyzed reaction Makes the connection between organic reaction mechanisms and enzyme mechanisms Compiles the latest information about molecular mechanisms of enzyme reactions Accompanied by clearly drawn structures, schemes, and figures Includes an extensive bibliography on enzyme mechanisms covering the last 30 years Explains how enzymes can accelerate the rates of chemical reactions with high specificity Provides approaches to the design of inhibitors of enzyme-catalyzed reactions Categorizes the cofactors that are appropriate for catalyzing different classes of reactions Shows how chemical enzyme models are used for mechanistic studies Describes catalytic antibody design and mechanism Includes problem sets and solutions for each chapter Written in an informal and didactic style
Download or read book The Development and Application of Thiosquaramides and Bispyridiniums as Hydrogen bond Donor Catalysts written by Michael Gregorio Rombola and published by . This book was released on 2018 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chiral hydrogen-bond donor molecules have emerged as powerful catalysts for asymmetric organic synthesis. Principles of hydrogen-bond donor catalyst design have led to the development of thiosquaramides and bispyridiniums as highly active catalysts. The synthesis and catalytic performance of thiosquaramide and bispyridinium catalophores is described, as well as their application to new methodologies, in particular highly enantioselective Michael additions of barbituric acids to nitroalkenes and nitro-Diels-Alder reactions.
Download or read book Enantioselective Organocatalysis written by Peter I. Dalko and published by John Wiley & Sons. This book was released on 2007-06-27 with total page 559 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this reference leaders at the forefront of research provide an insight into one of the hottest topics in organic synthesis, focusing on the most important enantioselective reactions. Clearly structured, each entry begins with a concise introduction, including a mechanistic discussion of the reaction, followed by preparative guidelines for newcomers, such as carefully selected working procedures with critical notes for bench chemists, rules of thumb and tips and tricks.
Download or read book Hydrogen Bonding in Organic Synthesis written by Petri M. Pihko and published by John Wiley & Sons. This book was released on 2009-09-09 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first comprehensive overview of the rapidly growing field emphasizes the use of hydrogen bonding as a tool for organic synthesis, especially catalysis. As such, it covers such topics as enzyme chemistry, organocatalysis and total synthesis, all unified by the unique advantages of hydrogen bonding in the construction of complex molecules from simple precursors. Providing everything you need to know, this is a definite must for every synthetic chemist in academia and industry.
Download or read book Contemporary Catalysis written by Paul C J Kamer and published by Royal Society of Chemistry. This book was released on 2017 with total page 897 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing an integrated approach to the various aspects of catalysis, this textbook is ideal for graduate students from catalysis, engineering, and organic synthesis.
Download or read book Anion Receptor Chemistry written by Jonathan L Sessler and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anion recognition plays a critical role in a range of biological processes, and a variety of receptors and carriers can be found throughout the natural world. Chemists working in the area of supramolecular chemistry have created a range of anion receptors, drawing inspiration from nature as well as their own inventive processes. This book traces the origins of anion recognition chemistry as a unique sub-field in supramolecular chemistry while illustrating the basic approaches currently being used to effect receptor design. The combination of biological overview and summary of current synthetic approaches provides a coverage that is both comprehensive and comprehensible. First, the authors detail the key design motifs that have been used to generate synthetic receptors and which are likely to provide the basis for further developments. They also highlight briefly some of the features that are present in naturally occurring anion recognition and transport systems and summarise the applications of anion recognition chemistry. Providing as it does a detailed review for practitioners in the field and a concise introduction to the topic for newcomers, Anion Receptor Chemistry reflects the current state of the art. Fully referenced and illustrated in colour, it is a welcome addition to the literature.
Download or read book Discrimination of Mobile Supramolecular Chirality written by Ayumi Imayoshi and published by Springer Nature. This book was released on 2021-11-18 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book proposes a novel concept for molecular recognition. In the field of asymmetric synthesis approaching the mature science, asymmetric discrimination and catalytic synthesis of chiral supramolecules still stand as unsolved problems. The extreme difficulty in asymmetric synthesis of such supramolecules may result from the mobile nature of supramolecular chirality. Here the author shows the first highly enantioselective synthesis of mechanically chiral supramolecules. In the presence of a chiral organocatalyst, a mechanically planar chiral rotaxane was obtained with p erfect enantiopurity (>99% ee) with an excellent selectivity. The dynamic and flexible recognition mode enabled asymmetric synthesis of supramolecules with conformational flexibility and mobility. The recognition mode of the catalyst is a contrast to the traditional static and rigid recognition mode of the typical conventional catalysts. The concept of dynamic molecular recognition will be adopted as a novel concept in a wide range of fields beyond the field of organic chemistry, including material chemistry, biochemistry, and medicinal chemistry.
Download or read book Anion Binding Catalysis written by Olga Garcia-Mancheno and published by John Wiley & Sons. This book was released on 2022-03-21 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Fundamentals of Asymmetric Catalysis written by Patrick J. Walsh and published by University Science Books. This book was released on 2009-01-02 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work describes the essential aspects of enantioselective catalysis, with chapters organised by concept rather than by reaction type. Each concept is supported by examples to give the reader broad exposure to a wide range of catalysts, reactions and reaction mechanisms.
Download or read book Organofluorine Chemistry written by Kalman J. Szabo and published by John Wiley & Sons. This book was released on 2021-03-22 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: By presenting novel methods for the efficient preparation of fluorinated compounds and their application in pharmaceutical and agrochemical chemistry as well as medicine, this is a valuable source of information for all researchers in academia and industry!
Download or read book Chiral Ferrocenes in Asymmetric Catalysis written by Li-Xin Dai and published by John Wiley & Sons. This book was released on 2010-02-01 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book meets the long-felt need for a reference on ferrocenes with the focus on catalysis. It provides a thorough overview of the synthesis and characterization of different types of chiral ferrocene ligands, their application to various catalytic asymmetric reactions, and versatile chiral materials as well as drug intermediates synthesized from them. Written by the "who's who" of ferrocene catalysis, this is a guide to the design of new ferrocene ligands and synthesis of chiral synthetic intermediates, and will thus be useful for organic, catalytic and synthetic chemists working in academia, industrial research or process development.
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 New Concepts and Applications in Chiral Br nsted Acid and Base Catalysis written by Chang Min and published by . This book was released on 2017 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chiral Brønsted acidic small molecules have found widespread applications as organocatalysts from the beginning of this century. Weaker Brønsted acids such as diols and (thio)ureas, typically classified as hydrogen bonding catalysts, and stronger phosphoric acids have proven to be highly effective in a wide range of asymmetric transformations. Chiral carboxylic acids, much less developed than those mentioned above, have recently drawn the attention of organic chemists as complementary Brønsted acid catalysts. Given that the pKa of a chiral carboxylic acid is expected to lie between that of most hydrogen bond donor and chiral phosphoric acid catalysts, it provides new potential to activate a different set of substrates requiring appropriate catalyst acidity. More importantly, by taking advantage of the judicious design of the catalyst structure, the acidity can be largely increased by the stabilization of the corresponding counterion via all kinds of interactions. This dissertation outlines the development of a new type of conjugate-base-stabilized carboxylic acid to solve the problems that have not been addressed by previously existing catalytic systems. In addition, the development of innovative synthetic applications of known chiral phosphoric acids is also detailed. Specific projects include the inter-, intramolecular Povarov reactions of secondary amines, kinetic resolution of indolines, the synthesis of polycyclic amines via an oxidative Povarov approach, the biomimetic enantioselective synthesis of isoindolinones and a dual-catalysis approach to the kinetic resolution of 1,2-diaryl-1,2-diaminoethanes.
