| Advisory Board | ||
| John E. Baldwin | Steven V. Ley | |
| Peter Beak | James A. Marshall | |
| Dale L. Boger | Michael J. Martinelli | |
| André B. Charette | Stuart W. Mc Combie | |
| Engelbert Ciganek | Scott J. Miller | |
| Dennis Curran | John Montgomery | |
| Samuel Danishefsky | Larry E. Overman | |
| Huw M. L. Davies | T. V. RajanBabu | |
| Scott E. Denmark | Hans J. Reich | |
| John Fried | James H. Rigby | |
| Jacquelyn Gervay‐Hague | William R. Roush | |
| Heinz W. Gschwend | Tomislav Rovis | |
| Stephen Hanessian | Scott D. Rychnovsky | |
| Louis Hegedus | Martin Semmelhack | |
| Paul J. Hergenrother | Charles Sih | |
| Jeffrey S. Johnson | Amos B. Smith, III | |
| Robert C. Kelly | Barry M. Trost | |
| Laura Kiessling | James D. White | |
| Marisa C. Kozlowski | Peter Wipf | |
| Former Members of the Board Now Deceased | ||
| Roger Adams | Herbert O. House | |
| Homer Adkins | John R. Johnson | |
| Werner E. Bachmann | Robert M. Joyce | |
| A. H. Blatt | Andrew S. Kende | |
| Robert Bittman | Willy Leimgruber | |
| Virgil Boekelheide | Frank C. Mc Grew | |
| George A. Boswell, Jr. | Blaine C. Mc Kusick | |
| Theodore L. Cairns | Jerrold Meinwald | |
| Arthur C. Cope | Carl Niemann | |
| Donald J. Cram | Leo A. Paquette | |
| David Y. Curtin | Gary H. Posner | |
| William G. Dauben | Harold R. Snyder | |
| Richard F. Heck | Milán Uskokovic | |
| Louis F. Fieser | Boris Weinstein | |
| Ralph F. Hirschmann | ||
Editorial Board
P. Andrew Evans, Editor-in-Chief
Steven M. Weinreb, Executive Editor
| Jeffrey Aubé | Jennifer A. Love |
| David B. Berkowitz | Gary A. Molander |
| Paul R. Blakemore | Albert Padwa |
| Jin K. Cha | Jennifer M. Schomaker |
| Dennis G. Hall | Kevin H. Shaughnessy |
| Donna M. Huryn | Christopher D. Vanderwal |
Jeffery B. Press, Secretary
Press Consulting Partners, Brewster, New York
Danielle Soenen, Editorial Coordinator
Dena Lindsay, Secretary and Processing Editor
Landy K. Blasdel, Processing Editor
Debra Dolliver, Processing Editor
Engelbert Ciganek, Editorial Advisor
ASSOCIATE EDITORS
Lu Gao
Daesung Lee
Zhenlei Song
Ivan Volchkov
Ya Wu
Wenyu Yang
Sang Young Yun
Copyright © 2020 by Organic Reactions, Inc. All rights reserved.
Published by John Wiley ,1& Sons, Inc., Hoboken, New Jersey
Published simultaneously in Canada
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Library of Congress Cataloging‐in‐Publication Data: ISBN: 978‐1‐119‐65122‐2
Printed in the United States of America
10 9 8 7 6 5 4 3 2 1
In the course of nearly every program of research in organic chemistry, the investigator finds it necessary to use several of the better‐known synthetic reactions. To discover the optimum conditions for the application of even the most familiar one to a compound not previously subjected to the reaction often requires an extensive search of the literature; even then a series of experiments may be necessary. When the results of the investigation are published, the synthesis, which may have required months of work, is usually described without comment. The background of knowledge and experience gained in the literature search and experimentation is thus lost to those who subsequently have occasion to apply the general method. The student of preparative organic chemistry faces similar difficulties. The textbooks and laboratory manuals furnish numerous examples of the application of various syntheses, but only rarely do they convey an accurate conception of the scope and usefulness of the processes.
For many years American organic chemists have discussed these problems. The plan of compiling critical discussions of the more important reactions thus was evolved. The volumes of Organic Reactions are collections of chapters each devoted to a single reaction, or a definite phase of a reaction, of wide applicability. The authors have had experience with the processes surveyed. The subjects are presented from the preparative viewpoint, and particular attention is given to limitations, interfering influences, effects of structure, and the selection of experimental techniques. Each chapter includes several detailed procedures illustrating the significant modifications of the method. Most of these procedures have been found satisfactory by the author or one of the editors, but unlike those in Organic Syntheses, they have not been subjected to careful testing in two or more laboratories. Each chapter contains tables that include all the examples of the reaction under consideration that the author has been able to find. It is inevitable, however, that in the search of the literature some examples will be missed, especially when the reaction is used as one step in an extended synthesis. Nevertheless, the investigator will be able to use the tables and their accompanying bibliographies in place of most or all of the literature search so often required. Because of the systematic arrangement of the material in the chapters and the entries in the tables, users of the books will be able to find information desired by reference to the table of contents of the appropriate chapter. In the interest of economy, the entries in the indices have been kept to a minimum, and, in particular, the compounds listed in the tables are not repeated in the indices.
The success of this publication, which will appear periodically, depends upon the cooperation of organic chemists and their willingness to devote time and effort to the preparation of the chapters. They have manifested their interest already by the almost unanimous acceptance of invitations to contribute to the work. The editors will welcome their continued interest and their suggestions for improvements in Organic Reactions.
In the intervening years since “The Chief” wrote this introduction to the second of his publishing creations, much in the world of chemistry has changed. In particular, the last decade has witnessed a revolution in the generation, dissemination, and availability of the chemical literature with the advent of electronic publication and abstracting services. Although the exponential growth in the chemical literature was one of the motivations for the creation of Organic Reactions, Adams could never have anticipated the impact of electronic access to the literature. Yet, as often happens with visionary advances, the value of this critical resource is now even greater than at its inception.
From 1942 to the 1980's the challenge that Organic Reactions successfully addressed was the difficulty in compiling an authoritative summary of a preparatively useful organic reaction from the primary literature. Practitioners interested in executing such a reaction (or simply learning about the features, advantages, and limitations of this process) would have a valuable resource to guide their experimentation. As abstracting services, in particular Chemical Abstracts and later Beilstein, entered the electronic age, the challenge for the practitioner was no longer to locate all of the literature on the subject. However, Organic Reactions chapters are much more than a surfeit of primary references; they constitute a distillation of this avalanche of information into the knowledge needed to correctly implement a reaction. It is in this capacity, namely to provide focused, scholarly, and comprehensive overviews of a given transformation, that Organic Reactions takes on even greater significance for the practice of chemical experimentation in the 21st century.
Adams' description of the content of the intended chapters is still remarkably relevant today. The development of new chemical reactions over the past decades has greatly accelerated and has embraced more sophisticated reagents derived from elements representing all reaches of the Periodic Table. Accordingly, the successful implementation of these transformations requires more stringent adherence to important experimental details and conditions. The suitability of a given reaction for an unknown application is best judged from the informed vantage point provided by precedent and guidelines offered by a knowledgeable author.
As Adams clearly understood, the ultimate success of the enterprise depends on the willingness of organic chemists to devote their time and efforts to the preparation of chapters. The fact that, at the dawn of the 21st century, the series continues to thrive is fitting testimony to those chemists whose contributions serve as the foundation of this edifice. Chemists who are considering the preparation of a manuscript for submission to Organic Reactions are urged to contact the Editor‐in‐Chief.
The man who moves a mountain begins by carrying away small stones.
Confucius, The Analects
The development of a new chemical reaction often begins with a preliminary discovery that, over time, blossoms into a vast body of chemical knowledge that is compiled by the synthetic community. Although there is undoubtedly an element of serendipity in the initial discovery, the hard work that translates the so‐called “small stones into a mountain” occurs over time through innovative contributions that facilitate the development of the transformation into a sophisticated and broad process. Hence, while the importance of a reaction is often underestimated at the outset, the delineation of detailed insights into scope and mechanism along with successful application to total synthesis drives the development of the process into an essential tool for all types of synthetic applications. The two chapters in this volume of Organic Reactions illustrate this notion and serve as examples of how a simple discovery can evolve into a sophisticated and powerful synthetic method, which, in one case, is recognized as a named reaction. Ironically, these two seemingly dissimilar reactions both involve processes where atoms “change places” in a predictable manner to permit the formation of important new C‐C bonds. Moreover, the reactions have been utilized to control both sp2 and sp3 stereochemistry, which permits new strategic thinking that would be challenging using conventional reactions.
The first chapter by Lu Gao, Wenyu Yang, Ya Wu, and Zhenlei Song is an outstanding treatise on the venerable Brook rearrangement. The research on this rearrangement dates back to the early 1950s when Adrian Brook discovered the rearrangement by accident while completing postdoctoral studies with Henry Gilman at Iowa State University. Thus, in the course of the attempted addition of triphenylsilylpotassium to benzophenone, he observed “an unexpected product” from the migration of the silyl group after nucleophilic addition into the carbonyl. During his independent career, Brook developed a detailed mechanistic understanding of this process, in which he demonstrated that the product is derived from the standard addition to the carbonyl group, followed by an intramolecular anionic carbon‐to‐oxygen silyl group migration to furnish a carbanion. This chapter now provides a complete summary of the mechanistic aspects of the reaction, which includes both anionic and neutral variants, in which the latter is further subdivided into radical and concerted processes. The fascination with this rearrangement has provided many significant contributions that have resulted in an arsenal of intramolecular carbon‐to‐oxygen silyl group migrations. The authors have nicely organized the Scope and Limitations section according to six types of organosilanes employed to generate the reactive silyl oxyanion intermediates, namely, acylsilanes, ketosilanes, epoxysilanes, hydroxysilanes, silyl carbanions, and silylmetallic species. The silane sections are then further subdivided by the terminating electrophile (e.g., carbonyl acceptors, electrophilic alkenes, epoxides, organohalides, heteroatom electrophiles, proton, etc.). The comprehensive Tabular Survey is primarily organized in a similar manner, which makes the identification of the optimal reaction and the associated conditions relatively simple for the reader. Overall, this is an outstanding chapter on an important named reaction, which I trust will be an essential primary reference for the synthetic community.
The second chapter by Daesung Lee, Ivan Volchkov, and Sang Young Yun delineates the historical development of alkyne metathesis, which has not been as extensively studied as the alkene variant. This process is very challenging and the chapter focusses on the merits of specific catalysts and how they perform in various scenarios. For instance, there have been significant developments in new catalysts since Bailey described the first metal‐catalyzed alkyne metathesis using tungsten trioxide and silica. The chapter compares and contrasts the utility of the in situ‐generated molybdenum‐based catalytic systems reported by Mortreux, the well‐defined molybdenum‐ and tungsten‐based catalysts with alkoxide and phenoxide ligands, and Fürstner's silanolate‐ligated molybdenum alkylidyne complexes. The new catalyst systems have significantly improved air and moisture stability, high catalytic activity, in addition to providing outstanding functional‐group compatibility, which has significantly broadened the scope and utility of alkyne metathesis. The Scope and Limitations section is organized into four main categories, namely alkyne cross‐metathesis (ACM), ring‐closing alkyne metathesis (RCAM), ring‐opening alkyne metathesis polymerization (ROAMP), and acyclic diyne metathesis polymerization (ADIMET). Notably, the chapter provides the reader with a perspective of the knowledge gaps in the context of the current limitations with specific classes of reactions, which thereby offers important research opportunities. Furthermore, the sections on the Applications to Synthesis and the Comparison with Other Methods outline the synthetic utility and the importance of this process over the most prominent alternatives. For instance, alkyne metathesis offers unique chemoselectivity and the ability to selectively prepare either the (E)‐ or (Z)‐olefin from the alkyne, which significantly contrasts conventional alkene metathesis reactions. The Tabular Survey mirrors the Scope and Limitations section, which is arranged based on the type of metathesis, namely homometathesis (albeit terminal alkyne metathesis is included in this section), cross‐metathesis, and ring‐closing metathesis. Overall, this chapter provides the reader with an outstanding opportunity to familiarize themselves with the current state‐of‐the‐art and critical knowledge gaps in this important area.
I would be remiss if I did not acknowledge the entire Organic Reactions Editorial Board for their collective efforts in steering the chapters through the various stages of the editorial process. I would like to particularly thank Jeffrey S. Johnson (Chapter 1) for his early efforts before I took it over and Jin K. Cha (Chapter 2), who served as the Responsible Editors and marshaled the chapters through the various phases of development. I am also deeply indebted to Dr. Danielle Soenen for her continuous efforts as the Editorial Coordinator; her knowledge of Organic Reactions is a critical component to maintaining consistency in the series. Dr. Dena Lindsay (Secretary to the Editorial Board) is thanked for coordinating the contributions of the authors, editors, and publishers. In addition, the Organic Reactions enterprise could not maintain the quality of production without the efforts of Steven Weinreb (Executive Editor), Dr. Linda S. Press (Editorial Consultant), Dr. Engelbert Ciganek (Editorial Advisor), Dr. Landy Blasdel (Processing Editor), and Dr. Debra Dolliver (Processing Editor). I would also like to acknowledge Dr. Jeffery Press (Secretary‐Treasurer) for his constant effort to keep everyone on task and his attention to making sure that we are fiscally solvent!
I am indebted to all the individuals that are dedicated to ensuring the quality of Organic Reactions. The unique format of the chapters, in conjunction with the collated tables of examples, make this series of reviews both unique and exceptionally useful to the practicing synthetic organic chemist.
P. Andrew Evans
Kingston
Ontario, Canada