Advanced Organic Chemistry Reactions, Mechanisms, and Structure new

Knowledge of organic chemistry continues to move ahead on many fronts. New journals continue to appear and older ones increase in frequency of publication and/or in number of papers published. This fourth edition of Advanced Organic Chemistry has been thoroughly revised to reflect this growth. Every topic retained from the third edition has been brought up to date. Changes, ranging from minor to extensive, have been made on virtually every page of the third edition. More than 5000 references have been added. However, no changes were made in the organization: The structure of the fourth edition is essentially the same as that of the second and the third. Like the first three editions, the fourth is intended to be a textbook for a course in advanced organic chemistry taken by students who have had the standard undergraduate organic

and physical chemistry courses.

I have attempted to give equal weight to the three fundamental aspects of the study of organic chemistry: reactions, mechanisms, and structure. A student who has completed a course based on this book should be able to approach the literature directly, with a sound knowledge of modern basic organic chemistry. I have treated lightly or not at all the major special areas of organic chemistry: terpenes, carbohydrates, proteins,

polymerization and electro chemical reactions, steroids, etc. It is my opinion that these topics are best approached after the first year of graduate study, when the fundamentals have been mastered, either in advanced courses, or directly, by consulting the many excellent books and review articles available on these subjects.

The organization is based on reaction types, so the student can be shown that despite the large number of organic reactions, a relatively few principles suffice to explain nearly all of them. Accordingly, the reactions-mechanisms section of this book (Part 2) is divided into 10 chapters, each concerned with a different type of reaction. In the first part of each chapter the appropriate basic mechanisms are discussed along with

considerations of reactivity and orientation, while the second part consists of numbered sections devoted to individual reactions, where the scope and the mechanism of each reaction are discussed. I have used numbered sections for the reactions, because I have found that students learn better when they are presented with clear outlines (for a further discussion of the arrangement of Part 2, see pp. 287-288).

Since the methods for the preparation of individual classes of compounds (e.g., ketones, nitriles, etc.) are not treated all in one place, an index has been provided (Appendix B) by use of which all methods for the preparation of a given type of compound will be found. For each reaction, a list of Organic Syntheses references is given. Thus for most reactions the student can consult actual examples in Organic

Syntheses. The structure of organic compounds is discussed in the first five chapters of Part 1.

This section provides a necessary background for understanding mechanisms and is also important in its own right. The discussion begins with chemical bonding and includes a chapter on stereochemistry. There follow two chapters on reaction mechanisms in general, one for ordinary reactions and the other for photochemical

reactions. Part 1 concludes with two more chapters that give further background to the study of mechanisms. In addition to reactions, mechanis ms, and structure, the student should have some familiarity with the literature of organic chemistry. A chapter devoted to this topic has been placed in Appendix A, though many teachers may wish to cover this material at the beginning of the course. In the third edition I included the new IUPAC names for organic transformations. Since then the rules have been broadened to cover additional cases; hence more such names are given in this edition. Furthermore, IUPAC has now published a new system for designating reaction mechanisms (see p. 290), and I now include some of the simpler of these new designations. In treating a subject as broad as the basic structures, reactions, and mechanisms of organic chemistry, it is obviously not possible to cover each topic in great depth. Nor would this be desirable even if possible. Nevertheless, students will often wish to pursue individual topics further. An effort has therefore been made to guide the reader to pertinent review articles and books published since about 1965. In this respect, this book is intended to be a guide to the secondary literature (since about 1965) of the

areas it covers. Furthermore, in a graduate course, students should be encouraged to consult primary sources. To this end, more than 15,000 references to original papers have been included. Although basically designed for a one- year course on the graduate level, this book can also be used in advanced undergraduate courses as long as they are preceded by oneyear courses in organic and physical chemistry. It can also be adapted, by the omission of a large part of its contents, to a one-semester course. Indeed, even for a

one-year course, more is included than can be conveniently covered. Many individual sections can be easily omitted without disturbing continuity. The reader will observe that this text contains much material that is included in firstyear organic and physical chemistry courses, though in most cases it goes more

deeply into each subject and, of course, provides references, which first- year texts do not. It has been my experience that students who have completed the first-year courses often have a hazy recollection of the material and greatly profit from a re-presentation of the material if it is organized in a different way. It is hoped that the organization of the material on reactions and mechanisms will greatly aid the memory and the understanding. In any given course the teacher may want to omit some chapters because the students already have an adequate knowledge of the material, or because there are other graduate courses that cover the areas more thoroughly. Chapters 1, 4, and 7 especially may fall into one of these categories.

Although this is a textbook, it has been designed to have reference value also. Students preparing for qualifying examinations and practicing organic chemists will find that Part 2 contains a survey of what is known about the mechanism and scope of about 580 reactions, arranged in an orderly manner based on reaction type and on which bonds are broken and formed. Also valuable for reference purposes are the previouslyand of all of the Organic Syntheses references to each reaction. Anyone who writes a book such as this is faced with the question of which units to use, in cases where international rules mandate one system, but published papers use another. Two instances are the units for energies and for bond distances. For energies, IUPAC mandates joules, and many journals do use this unit exclusively. However,

organic chemists who publish in United States journals overwhelmingly use calories and this situation shows no signs of changing in the near future. Since previous editions of this book have been used extensively both in this country and abroad, I have now adopted the practice of giving virtually all energy values in both calories and joules. The question of units for bond distances is easier to answer. Although IUPAC

does not recommend Angstrom units, nearly all bond distances published in the literature anywhere in the world, whether in organic or in crystallographic journals, are in these units, though a few papers do use picometers. Therefore, I continue to use only Angstrom units.