Author: Byeong-Seon Kim
Publisher:
ISBN:
Category :
Languages : en
Pages : 856
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Book Description
Transition metal-catalyzed reactions are rapidly being developed for the synthesis complex natural and non-natural products. Among these, palladium-catalyzed reactions are both attractive and reliable. However, a formidable challenge at the forefront of organic chemistry is the control of selectivity to enable the selective formation of diverse structural motifs from readily available substrate classes. Herein, progress toward broadening the scope of palladium-catalyzed C-C bond-forming reactions is demonstrated, with a particular focus on controlling reactivity, regioselectivity, and chemoselectivity.
Author: Lien-Chung Kao
Publisher:
ISBN:
Category : Palladium catalysts
Languages : en
Pages : 218
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Book Description
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: David Andrew Thaisrivongs
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The research described in this dissertation defines two endeavors into the field of palladium-catalyzed allylic alkylation chemistry: the employment of unstabilized nitrogen-containing aromatic heterocycles as nucleophiles and the use of C--H activation to access [pi]-allyl-palladium electrophiles. With regard to the former program, we demonstrate that 2-methylpyridines, substrates whose corresponding anions are too unstabilized to react productively in palladium-catalyzed asymmetric allylic alkylation (AAA) reactions, form complexes when exposed to boron trifluoride diethyl etherate that can be deprotonated with lithium hexamethyldisilazide to afford competent nucleophiles for AAA processes. Investigations into the reaction mechanism establish that the configuration of the allylic stereocenter of the electrophile is retained, a finding that is consistent with the canonical outer sphere mechanism invoked for palladium-catalyzed allylic substitution processes of stabilized anions. We also show that under modified conditions, this protocol is applicable to the highly regio-, diastereo-, and enantioselective allylic alkylation of 2-substituted pyridines, reactions that form homoallylic stereocenters containing alkyl, aryl, heteroaryl, and nitrogen substituents. When the reaction is correspondingly performed with unsymmetric acyclic electrophiles, both linear and branched products may be obtained regio- and enantioselectively by choosing the appropriate regioisomeric starting material and ligand. We further report that this strategy extends to reactions of a variety of nitrogen-containing aromatic heterocycles, including pyrazines, pyrimidines, pyridazines, quinoxalines, benzoimidazoles, and tetrazoles. The mesityl ester, whose steric bulk prevents competitive deacylation of the electrophile from these nucleophiles, is introduced as a new leaving group in allylic alkylation chemistry. We describe the first general palladium-catalyzed allylic alkylation of 1,4-dienes that proceeds via C--H activation. A broad range of nucleophiles undergo reaction with variously substituted 1,4-dienes under relatively mild conditions, providing direct access to the corresponding 1,3-diene-containing products with high regio- and stereocontrol. This is the first catalytic allylic alkylation that proceeds via C--H activation in the absence of sulfoxide ligands, a discovery that provides for further developments in this chemistry enabled by phosphorus-based ligands. This finding is applied to a new assisted tandem catalytic process that effects sequential palladium(0)-catalyzed allylic alkylations via leaving group ionization and palladium(II)-catalyzed allylic alkylations via C--H activation. By employing an oxidative trigger to convert the initial palladium(0) species to a palladium(II) one, both transformations can be conducted in a single reaction vessel using the same precatalyst. This strategy allows for the introduction of otherwise indistinguishable allyl groups by exploiting complementary catalytic redox cycles. Finally, we detail the discovery and development of the first catalytic enantioselective palladium-catalyzed allylic C--H alkylations, an achievement made possible by a novel class of pyroglutamic-based phosphoramidite ligands. A wide array of sterically and electronically diverse allylarenes undergo allylic substitution by 2-acetyl-1-tetralones to form quaternary carbon stereocenters. Control experiments verify that this palladium-catalyzed process involves direct allylic alkylation, rather than initial allylic C--H acetoxylation. This conceptually and mechanistically distinct strategy averts many of the chemoselectivity issues inherent to traditional methods for the synthesis of enantioenriched allylic substitution products, providing the groundwork for the next generation of palladium-catalyzed allylic alkylation methods.
Author: Patrick J. Walsh
Publisher: University Science Books
ISBN: 9781891389542
Category : Science
Languages : en
Pages : 692
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Book Description
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.
Author: Yasushi Nishihara
Publisher: Springer Science & Business Media
ISBN: 3642323685
Category : Science
Languages : en
Pages : 247
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Book Description
“Applied Cross-Coupling Reactions” provides students and teachers of advanced organic chemistry with an overview of the history, mechanisms and applications of cross-coupling reactions. Since the discovery of the transition-metal-catalyzed cross-coupling reactions in 1972, numerous synthetic uses and industrial applications have been developed. The mechanistic studies of the cross-coupling reactions have disclosed that three fundamental reactions: oxidative addition, transmetalation, and reductive elimination, are involved in a catalytic cycle. Cross-coupling reactions have allowed us to produce a variety of compounds for industrial purposes, such as natural products, pharmaceuticals, liquid crystals and conjugate polymers for use in electronic devices. Indeed, the Nobel Prize for Chemistry in 2010 was awarded for work on cross-coupling reactions. In this book, the recent trends in cross-coupling reactions are also introduced from the point of view of synthesis design and catalytic activities of transition-metal catalysts.
Author: Florencio Zaragoza Dörwald
Publisher: John Wiley & Sons
ISBN: 3527604987
Category : Science
Languages : en
Pages : 389
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Book Description
Most syntheses in the chemical research laboratory fail and usually require several attempts before proceeding satisfactorily. Failed syntheses are not only discouraging and frustrating, but also cost a lot of time and money. Many failures may, however, be avoided by understanding the structure-reactivity relationship of organic compounds. This textbook highlights the competing processes and limitations of the most important reactions used in organic synthesis. By allowing chemists to quickly recognize potential problems this book will help to improve their efficiency and success-rate. A must for every graduate student but also for every chemist in industry and academia. Contents: 1 Organic Synthesis: General Remarks 2 Stereoelectronic Effects and Reactivity 3 The Stability of Organic Compounds 4 Aliphatic Nucleophilic Substitutions: Problematic Electrophiles 5 The Alkylation of Carbanions 6 The Alkylation of Heteroatoms 7 The Acylation of Heteroatoms 8 Palladium-Catalyzed C-C Bond Formation 9 Cyclizations 10 Monofunctionalization of Symmetric Difunctional Substrates
Author: Eric F.V. Scriven
Publisher: Academic Press
ISBN: 0123852366
Category : Science
Languages : en
Pages : 583
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Book Description
Pyridines: From Lab to Production provides a synthetic armory of tools to aid the practicing chemist by reviewing the most reliable historical methods alongside new methods/ Written by scientists who have actually used these in synthesis. By emphasizing tricks and tips to optimize reactions for the best yields and purity, which are often missing from the primary literature, this book provides another dimension for the synthetic chemist. A combined academic and industrial approach evaluates the best methods for different scales of reaction and discusses practical tips (e.g. when to stop a reaction early to maximize purity or when to re-use side products). Chapters also assess whether to make or source starting materials, how to connect them and what are the best synthetic routes. The book is designed to be a stand-alone reference, but also provides cross references to leading reviews and the Comprehensive Heterocyclic Chemistry reference works for those who want to learn more. Reviews tried and tested practical methods to help the reader select the best method for their research Includes tips, tricks and hints to enable the reader to get the best yield or cleanest product out of their reaction for synthesising or transforming a pyridine derivative Written by both academic researchers and industry leaders this provides a unique view of how to get the most out of a reaction no matter what scale you are running this on
Author: Dennis G. Hall
Publisher: John Wiley & Sons
ISBN: 3527606823
Category : Science
Languages : en
Pages : 571
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Book Description
For the first time, the whole field of organoboronic acids is presented in one comprehensive handbook. Professor Dennis Hall, a rising star within the community, covers all aspects of this important substance class, including applications in chemistry, biology and medicine. Starting with an introduction to the structure, properties, and preparation of boronic acid derivatives, together with an overview of their reactions and applications, the book goes on to look at metal-catalyzed borylation of alkanes and arenas, coupling reactions and rhodium-catalyzed additions of boronic acids to alkenes and carbonyl compounds. There follows chapters on copper-promoted C-O and C-N cross-coupling of boronic acids, recent applications in organic synthesis, as well as alpha-haloalkylboronic esters in asymmetric synthesis. Later sections deal with cycloadditions, organoboronic acids, oxazaborolidines as asymmetric inducers, and boronic acid based receptors and sensors. The whole is rounded off with experimental procedures, making this invaluable reading for organic, catalytic and medicinal chemists, as well as those working in organometallics.
Author: Paul C. Howard
Publisher: Springer Science & Business Media
ISBN: 1461538009
Category : Science
Languages : en
Pages : 324
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Book Description
Prior to 1979, consideration of the problem of the carcinogenicity of the aromatic amine class of chemicals took place primarily in poster sessions and symposia of annual meetings of the American Association for Cancer Research and analogous international associations. In November 1979 the first meeting concerned with the aromatic amines was held in Rockville, Haryland under primary sponsorship of the National Cancer Institute. The proceedings from this meeting were published as Monograph 58 of the Journal of the National Cancel' Institute in 1981. The second meeting in this series, the Second International Conference on N-Substituted Aryl Compounds, was held in March/April of 1982 in Hot Springs, Arkansas. The National Cancer Institute and The National Center for Toxicological Research were the primary sponsors of this meeting. The proceedings were published as Volume 49 of the journal En-vil'onmental Health Perspectives in 1983. The third meeting in this series was held in April of 1987 at the Dearborn Hyatt in Dearborn, Michigan. The principal sponsor of this meeting was the Heyer L. Pre ntis Comprehensive Cancer Center of Metropolitan Detroit. The proceedings, Carcinogenic and Mutagenic Responses to Aromatic Amines and Nitroal'enes, were published in 1987 by Elsevier Press. The fourth meeting was held in Cleveland, Ohio, on July 15-19, 1989.
