Asymmetric Synthesis

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.

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.

Asymmetric synthesis is an integral part of synthetic organic chemistry. Some of the reactions in this book were known prior to 1980, while several new ones, particularly catalytic asymmetric reactions, have been discovered in the recent years. The impact of this new class of reactions has been impressively extensive—both on organic and medicinal chemistry. These reactions have been accepted whole-heartedly by synthetic organic chemists in developing shorter routes for complex natural targets as well as in the manufacture of a wide range of drug intermediates.

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.

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.

Here, all aspects of the topic are presented in a compact manner. The book is clearly structured, and divided into two sections -- asymmetric synthesis of heterocycles containing only one nitrogen and that of those with more than one nitrogen as a heteroatom -- such that the necessary information may be found at a glance. The international team of authors provides important experimental procedures, including industrial applications. Essential for synthetic chemists in pharmaceutical and agrochemical chemistry.

Asymmetric Synthesis of Natural Products Fully updated learning resource covering the concept of using natural product chemistry for strategies in asymmetric synthesis The third edition of Asymmetric Synthesis of Natural Products introduces students to the rapidly growing field of natural products in organic chemistry, discussing the practical, mainly pharmacological, importance of selected compounds and emphasizing the target-oriented approach of organic synthesis which is key in industrial strategies. To aid in reader comprehension, the text includes key references and an Index of Compounds. The textbook is based on two lecture courses (Asymmetric Synthesis & Asymmetric Synthesis of Natural Products), which the author has delivered more than 50 times over the past 20 years in Finland, the UK, Italy, and Greece. This third edition is fully updated from the earlier versions (published by Wiley in 1993 and 2012). The importance of natural products as truly renewable raw materials in sustainable chemistry and circular economy is illustrated through applications of e.g. organocatalysis, organometallic catalysis, and biocatalysis. The contents consist of traditional text supplemented with illustrations (such as chemical drawings and structural formulae). Three dimensional aspects are also discussed with the use of 3D renderings of structures for both reaction mechanisms (molecular modeling) and crystallographic data. Sample topics covered in the textbook include: The foundations of asymmetric synthesis, including the theory and applications of individual asymmetric reactions Sustainable development, the circular economy, and use of renewable raw materials that have become prominent in many fields of science and technology Various natural product classes, including carbohydrates, amino acids, peptides, proteins, nucleosides, nucleotides, nucleic acids, and polyketides The properties of these natural product classes, including their structures, biosynthesis, and interrelationships, as well as examples of asymmetric syntheses and the practical value of these compounds Asymmetric Synthesis of Natural Products is a comprehensive, authoritative, and up-to-date learning resource on the subject for advanced level undergraduate or early-stage graduate students. It is also useful for specialists already working in synthesis who wish to learn about asymmetric synthesis.

After the overwhelming success of Asymmetric Synthesis - The Essentials, displaying a broad range of organic asymmetric syntheses, this is the second edition with latest subjects and authors. While the aim of the first edition was mainly to honor the achievements of the pioneers in asymmetric syntheses, the aim of this new edition was bringing the current developments, especially from younger colleagues, to the attention of students. The format of the book remained unchanged, i.e. short conceptual overviews by young leaders in their field including a short biography of the authors. The growing multidisciplinary research within chemistry is reflected in the selection of topics including metal catalysis, organocatalysis, physical organic chemistry, analytical chemistry, and its applications in total synthesis, materials research and industry. The prospective reader of this book is a graduate or undergraduate student of advanced organic chemistry as well as the industrial chemist who wants to get a brief update on the current developments in the field.