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Library of Congress Cataloging-in-Publication Data:
ISBN: 978-1-119-28143-6
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 authors have 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.
Fluorine has to be the most schizophrenic element in the Periodic Table. In its nascent form it is the most reactive element, combining indiscriminately and exothermically with anything it contacts. However, once bound into organic compounds, it renders them extremely inert, thus imbuing them with highly valued properties in products that permeate our everyday lives. Mario Markus sums it up beautifully in his Chemical Poems: One for Each Element, in which he juxtaposes the dichotomy of hyperreactivity and civility; “The homicidal maniac blinds or kills whoever comes near…..Why? Because he wants an electron, that's all. Let us give him the pittance that he wants. Now we see how calm he becomes…” The inertness of organofluorine compounds leads to myriad applications from non-stick frying pans to refrigerants to medical implants.
However, for the synthetic organic chemist, the extraordinary chemical stability of carbon-fluorine bonds has found widespread application in fine-tuning the physico-chemical properties of pharmaceutical, agrochemical, and liquid crystalline substances. In particular the trifluoromethyl group has become a highly prized substituent by dint of its high electronegativity, lipophilicity, steric size, and resistance to chemical degradation by oxidative, reductive, hydrolytic, photolytic, and thermal insults. Given the broad utility of the trifluoromethyl group, it is not surprising that the number of methods for selective and efficient introduction of this group into many different organic substrates has been a major focus of research for the past decades. This field has grown so rapidly with so many important advances that it would be impossible to comprehensively cover all such methods even in a single volume of Organic Reactions. Accordingly, Volume 91 contains a single chapter dedicated to one of the most useful methods for introducing a perfluoroalkyl group, namely nucleophilic perfluoroalkylation.
We are extremely fortunate that three of the worlds' leading experts on nucleophilic perfluoroalkylation have teamed up to produce the first, comprehensive treatment of this extremely important transformation. Prof. Petr Beier, Dr. Mikhail Zibinsky, and Prof. G. K. Surya Prakash have combined their many years of first-hand research experience and encyclopedic knowledge of the field in a massive, but yet highly accessible and authoritative treatise covering all of the methods for delivering perfluoroalkyl groups from dozens of different sources to scores of different substrates. The resulting matrix of possibilities for combinations of perfluoroalkyl donor and organic acceptor would inevitably paralyze the practitioner with a bewildering abundance of options. In view of this challenge, the authors have provided tabular listings of the recommended reagents for perfluoroalkylation of the most common substrates. Even if one is not immediately interested in performing a perfluoroalkylation, reading this chapter provides a fascinating overview of the extraordinary diversity of donors ranging from the ubiquitous Rupert-Prakash reagent (trifluoromethyltrimethylsilane) to perfluoroalkyltellurium reagents to perfluoroalkyllithium, −indium, −copper, −silver, and -zinc reagents. A still greater congregation of electrophiles is covered ranging from organohalides to carbonyl groups to azomethines to carboxyl derivatives all the way to Main Group and Transition Metal electrophiles and even xenon! Finally, the most recent advances for introducing perfluoroalkyl groups with control of newly created stereogenic centers are also covered.
The Tabular Survey contains over 540 pages of all examples of nucleophilic perfluoroalkylation contained in the literature through the first quarter of 2014. The tables are organized by electrophilic substrate, thus allowing the reader to quickly locate the class of compounds of specific interest. Moreover, extensive subtables have been compiled that allow direct comparison of different methods that have been applied to a given substrate, thus facilitating an immediate evaluation of the appropriate choice for that specific target.
Volume 91 represents the thirteenth single chapter volume to be produced in our 75-year history (the fourth in a row and sixth in the past twelve volumes!). Such single-chapter volumes represent definitive treatises on extremely important chemical transformations. The organic chemistry community owes an enormous debt of gratitude to the authors of such chapters for the generous contribution of their time, effort, and insights on reactions that we clearly value.
It is appropriate here to acknowledge the expert assistance of the entire editorial board, in particular Michael Martinelli who oversaw the early development of this chapter. The contributions of the authors, editors, and the publisher were expertly coordinated by the board secretary, Robert M. Coates. In addition, the Organic Reactions enterprise could not maintain the quality of production without the dedicated efforts of its editorial staff, Dr. Danielle Soenen, Dr. Linda S. Press, Ms. Dena Lindsey, and Dr. Landy Blasdel. Insofar as the essence of Organic Reactions chapters resides in the massive tables of examples, the authors' and editorial coordinators' painstaking efforts are highly prized.
Scott E. Denmark
Urbana, Illinois