Page 9 - Mechanism and Theory in Organic Chemistry

x Preface
the ideas and method of thinking associated with the pericyclic theory will have
an increasing impact in both organic and inorganic chemistry in the future, we
have given a more detailed discussion of its purely theoretical aspects than has
heretofore been customary in books of this kind. This discussion includes both
the Woodward-Hoffmann approach and the Dewar-Zimmerman aromaticity
approach and makes the connection between them. Our treatment requires as
background a more sophisticated understanding of covalent bonding than is
ordinarily given in introductory courses; we have therefore included an exten-
sive presentation of bonding theory. It begins at a basic level with a review of
familiar concepts in Chapter 1 and introduces in Chapter 10 the terminology
and ideas needed to understand the pericyclic theory and its ramifications. The
treatment is qualitative throughout. Although quantitative molecular orbital
calculations are not needed for our purposes, Appendix 2 to Chapter 1 sum-
marizes the molecular orbital calculation methods in general use. The Hiickel
MO method is covered in sufficient detail to allow the reader to apply it to
simple systems.
Another innovation in this text is the use of three-dimensional reaction
coordinate diagrams, pioneered by Thornton, More O'Ferrall, and Jencks, in
the discussions of nucleophilic substitutions, eliminations, and acid catalysis of
carbonyl additions. We hope that the examples may lead to more widespread
use of these highly informative diagrams.
A chapter on photochemistry provides a discussion of photophysical
processes needed as background for this increasingly important area of chemistry
and treats the main categories of light-induced reactions,
The text assumes elementary knowledge of the common organic spectro-
scopic techniques. Nevertheless, we have included a description of the recently
developed method of chemically induced dynamic nuclear polarization
(CIDNP), which has already proved to be of great importance in the study of
radical reactions and which has not yet found its way into books covering
spectroscopy of organic compounds.
Problems of varying difficulty have been included at the ends of the
chapters. Some problems illustrate points discussed in the text, but others are
meant to extend the text by leading the student to investigate reactions, or
even whole categories of reactions, which we have had to omit because of
limitations of space. References to review articles and to original literature are
given for all problems except those restricted to illustration of points that the
text discusses in detail. Problems that represent significant extensions of the
text are included in the index.
The book is extensively footnoted. It is neither possible nor desirable in
a book of this kind to present exhaustive reviews of the topics taken up, and we
have made no effort to give complete references. We have tried to include
references to review articles and monographs wherever recent ones are avail-
able, to provide key references to the original literature for the ideas discussed,
and to give sources for all factual information presented. The text also contains
numerous cross references.
The amount of material included is sufficient for a full-year course. For
a one-semester course, after review of the first two chapters, material may be
chosen to emphasize heterolytic reactions (Chapters 3-8), to cover a broader