Mechanism and Structure in Organic Chemistry [antikvár]

Preface i ,. « i i, As A RESULT of the very striking growth of physical organic chemistry during the last thirty years, nearly all colleges and universities that grant advanced degrees in chemistry offer at least one course in this field to graduates, and some offer such a course to promising undergraduates as well. Moreover, many chemists who obtained their degrees during the 1930's or 1940's have felt the need to familiarize themselves with this subject, for much of the most interesting research being carried out today in organic chemistry is strongly influenced by mechanistic thinking. The bulk of this text is devoted to the consideration of the mechanisms of homogeneous organic reactions, but the first three chapters are structural in outlook. These deal with the structures of atoms and organic molecules and with some of the physicochemical methods used to determine the positions of atoms and to study the distribution of electronic charge. The treatments here, although in accord with modern structural thought, tend to be brief; and, in some cases, the approach is descriptive rather than rigorous. These chapters are included because it is now clear that a satisfactory understanding of many organic chemical phenomena cannot be obtained if molecules are visualized merely as "ball-and-stick" models and atoms as miniature "solar systems." Much of the material in these chapters could be presented equally appropriately in texts in inorganic and physical chemistry; and those who, in previous training, have become familiar with the fundamentals of structural chemistry may wish to start directly with Chapter 4. A major difference between this text and others in the same field is the incorporation of a rather large number of exercises at the end of each of the sixteen chapters. It is intended that these develop the reader's ability to suggest mechanisms from experimental data, to relate structure to reactivity in many different situations, to predict the course of reactions which are new to him, to explain features about reactions which might otherwise puzzle him, and, if possible, to propose experiments which serve to distinguish between a number of possible mechanisms. Some of the exercises are relatively straightforward, but many require considerable thought. Some, I hope, will challenge the efforts of even the most capable readers. The level of difficulty in the text and in the exercises rises markedly as the reader passes from the earlier to the later chapters. Such a trend is desirable, for ill