Author: David John Ager
Publisher: CRC Press
ISBN: 9780849389429
Category : Science
Languages : en
Pages : 506
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Book Description
This comprehensive text presents a critical discussion of the scopes and limitations of various organic synthetic methodologies that are available for performing asymmetric transformations. In addition to purely chemical methods, the book covers applications of new enzymes and other biological systems that are increasingly useful in asymmetric methodology.
Author: R.E. Gawley
Publisher: Elsevier
ISBN: 0080514774
Category : Science
Languages : en
Pages : 395
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Book Description
The world is chiral. Most of the molecules in it are chiral, and asymmetric synthesis is an important means by which enantiopure chiral molecules may be obtained for study and sale. Using examples from the literature of asymmetric synthesis (more than 1300 references), the aim of this book is to present a detailed analysis of the factors that govern stereoselectivity in organic reactions. It is important to note that the references were each individually checked by the authors to verify relevance to the topics under discussion. The study of stereoselectivity has evolved from issues of diastereoselectivity, through auxiliary-based methods for the synthesis of enantiomerically pure compounds (diastereoselectivity followed by separation and auxiliary cleavage), to asymmetric catalysis. In the latter instance, enantiomers (not diastereomers) are the products, and highly selective reactions and modern purification techniques allow preparation - in a single step - of chiral substances in 99% ee for many reaction types. After an explanation of the basic physical-organic principles of stereoselectivity, the authors provide a detailed, annotated glossary of stereochemical terms. A chapter on "Analytical Methods" provides a critical overview of the most common methods for analysis of stereoisomers. The authors then follow the 'tried-and-true' format of grouping the material by reaction type. Thus, there are four chapters on carbon-carbon bond forming reactions (enolate alkylations, organometal additions to carbonyls, aldol and Michael reactions, and cycloadditions and rearrangements), one chapter on reductions and hydroborations (carbon-hydrogen bond forming reactions), and one on oxidations (carbon-oxygen and carbon-nitrogen bond forming reactions). Leading references are provided to natural product synthesis that have been accomplished using a given reaction as a key step. In addition to tables of examples that show high selectivity, a transition state analysis is presented to explain - to the current level of understanding - the stereoselectivity of each reaction. In one case (Cram's rule) the evolution of the current theory is detailed from its first tentative (1952) postulate to the current Felkin-Anh-Heathcock formalism. For other reactions, only the currently accepted rationale is presented. Examination of these rationales also exposes the weaknesses of current theories, in that they cannot always explain the experimental observations. These shortcomings provide a challenge for future mechanistic investigations.
Author: Guo-Qiang Lin
Publisher: John Wiley & Sons
ISBN: 0471465240
Category : Science
Languages : en
Pages : 536
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Book Description
Asymmetric synthesis remains a challenge to practicing scientistsas the need for enantiomerically pure or enriched compoundscontinues to increase. Over the last decade, a large amount ofliterature has been published in this field. Principles andApplications of Asymmetric Synthesis consolidates and evaluates themost useful methodologies into a one-volume resource for theconvenience of practicing scientists and students. Authored by internationally renowned scientists in the field, thisreliable reference covers more than 450 reactions and includesimportant stoichiometric as well as catalytic asymmetric reactions.The first chapter reviews the basic principles, commonnomenclature, and analytical methods, and the remainder of the bookis organized according to reaction type. The text examines suchtopics as: Carbon-carbon bond formations involving carbonyls, enamines,imines, and enolates Asymmetric C-O bond formations including epoxidation,dihydroxylation, and aminohydroxylation Asymmetric synthesis using the Diels-Alder reaction and othercyclizations Applications to the total synthesis of natural products Use of enzymes in asymmetric synthesis Practicing chemists in the pharmaceutical, fine chemical, andagricultural professions as well as graduate students will findthat Principles and Applications of Asymmetric Synthesis affordscomprehensive and current coverage.
Author: Michelangelo Gruttadauria
Publisher: John Wiley & Sons
ISBN: 1118087984
Category : Science
Languages : en
Pages : 721
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Book Description
This book covers advances in the methods of catalytic asymmetric synthesis and their applications. Coverage moves from new materials and technologies to homogeneous metal-free catalysts and homogeneous metal catalysts. The applications of several methodologies for the synthesis of biologically active molecules are discussed. Part I addresses recent advances in new materials and technologies such as supported catalysts, supports, self-supported catalysts, chiral ionic liquids, supercritical fluids, flow reactors and microwaves related to asymmetric catalysis. Part II covers advances and milestones in organocatalytic, enzymatic and metal-based mediated asymmetric synthesis, including applications for the synthesis of biologically active molecules. Written by leading international experts, this book consists of 16 chapters with 2000 References and illustrations of 560 schemes and figures.
Author: Vitomir Šunjić
Publisher: Springer
ISBN: 3319299263
Category : Science
Languages : en
Pages : 221
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Book Description
This book connects a retrosynthetic or disconnection approach with synthetic methods in the preparation of target molecules from simple, achiral ones to complex, chiral structures in the optically pure form. Retrosynthetic considerations and asymmetric syntheses are presented as closely related topics, often in the same chapter, underlining the importance of retrosynthetic consideration of target molecules neglecting stereochemistry and equipping readers to overcome the difficulties they may encounter in the planning and experimental implementation of asymmetric syntheses. This approach prepares students in advanced organic chemistry courses, and in particular young scientists working at academic and industrial laboratories, for independently solving synthetic problems and creating proposals for the synthesis of complex structures.
Author: David John Ager
Publisher: CRC Press
ISBN: 1000142477
Category : Science
Languages : en
Pages : 506
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Book Description
This comprehensive text presents a critical discussion of the scopes and limitations of various organic synthetic methodologies that are available for performing asymmetric transformations. In addition to purely chemical methods, the book covers applications of new enzymes and other biological systems that are increasingly useful in asymmetric methodology.
Author: Vicente Gotor
Publisher: John Wiley & Sons
ISBN: 3527622497
Category : Science
Languages : en
Pages : 340
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Book Description
Perfect for biochemists, synthetic and organic chemists, this book covers all important reactions, including C-C coupling reactions, oxidation reactions and many more. Divided into two parts, the first section on methodology presents new innovative methods for enzymatic catalysis optimization, including such new trends as medium engineering, directed evolution and computer-aided prediction of enantioselectivity. The second and main section deals with applications to synthesis, showing important reaction types and their applications. Only those reactions with very high selectivity are presented, allowing readers to improve their own reaction yields.
Author: Alan Aitken
Publisher: CRC Press
ISBN: 9780751401905
Category : Science
Languages : en
Pages : 256
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Book Description
Asymmetric synthesis is one of the most important areas of research and development in synthetic organic chemistry, and has wide-ranging industrial applications. This introduction to the subject covers chirality, nomenclature and analytical methods of resolution. The main body of the text describes the principal methods available to the organic chemist wishing to synthesize chiral compounds. Case studies are included, and reference sections allow access to the relevant review and research literature. This book is written for organic chemists at postgraduate and advanced undergraduate level.
Author: Maxime R Vitale
Publisher: Elsevier
ISBN: 0081011555
Category : Technology & Engineering
Languages : en
Pages : 186
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Book Description
Considering the challenge of sustainability facing our society in the coming decades, catalysis is without any doubt a research area of major importance. In this regard, asymmetric organocatalysis, now considered a pillar of green chemistry, deserves particular attention. The first chapter of this volume examines the topic of asymmetric organocatalysis in light of radical chemistry. Recent important progress in this field has been attained by promoting the formation and harnessing the high reactivity of open-shell intermediates. Merging organocatalysis with radical chemistry has been the key to solving some longstanding bottlenecks, and has also significantly contributed to reinforcing the key role of organocatalysis in asymmetric catalysis. This chapter presents the most significant developments in this area, with a particular focus on asymmetric SOMO- and photoredox-organocatalyzed transformations. Chapter 2 focuses on quaternary ammonium salts (R4N+X-), especially chiral derivatives, and their behavior as unique catalysts in organocatalysis. Forming chiral ion-pairs capable of promoting asymmetric reactions, they also operate as unique "transporters involved in phase transfer catalytic processes between liquid–liquid or liquid–solid systems. Furthermore, they offer unique opportunities when forming cooperative ion-paired entities R4N+X-, allowing a synergistic implication of the counter-ion X- either as Brønsted bases or Lewis bases. Specific design of such chiral catalysts in modern chemistry and better insight into their mode of activation facilitates efficient and unprecedented chemical transformations. This chapter provides an overview of the use of chiral quaternary ammonium salts in organocatalysis, emphasizing both general mechanistic aspects and the scope of this approach. - Presents the most significant developments with a particular focus on asymmetric SOMO- and photoredox-organocatalyzed transformations - Givies a larger overview of chiral ammonium salts in organocatalysis rather than a specific review dedicated to specialists in this area - Affords a historical evolution of this field of research
Author: Oleg I. Kolodiazhnyi
Publisher: John Wiley & Sons
ISBN: 3527341501
Category : Science
Languages : en
Pages : 392
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Book Description
Authored by one of the leading experts in the field, this is the only comprehensive overview of chiral organophosphorus compounds, from asymmetric synthesis to catalysis and pharmacological applications. As such, this unique reference covers the chemical background as well as spectroscopical analysis of phosphorus compounds, and thoroughly describes all the various synthetic strategies for these substances. Metal-, organo- and biocatalyzed reactions for the introduction of phosphorus are explained as are asymmetric oxidation and reduction methods for the preparation of all possible oxidation states of phosphorus. The text also includes industrial applications for these compounds. Of particular interest to chemists working in the field of asymmetric synthesis, as well as to the pharmaceutical industry due to the increasing number of phosphorous-containing drugs.
