Organic Reaction Mechanisms: An Introduction

292 Pages·14.395 MB·English

by  Ronald Breslow

RONALD BRESLOW
second edition
ORGANIC
REACTION
MECHANISMS
An
Introduction
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ORGANIC REACTION MECHANISMS
Second Edition
THE ORGANIC CHEMISTRY
MONOGRAPH SERIES
Ronald Breslow, editor
Columbia University
editorial advisory board: P. D. Bartlett, Harvard University
David Curtin, University of Illinois
W. S. Johnson, Stanford University
J. D. Roberts, California Institute of
Technology
R. B. Woodward, Harvard University
ORGANIC REACTION MECHANISMS, SECOND EDITION
RonaldBreslow
Columbia University
THE MOLECULES OF NATURE
James Hendrickson
Brandeis University
MODERN SYNTHETIC REACTIONS
HerbertHouse
MassachusettsInstituteof Technology
PEPTIDES AND AMINO ACIDS
Kenneth D. Kopple
Illinois Institute ofTechnology
INTRODUCTION TO STEREOCHEMISTRY
Kurt Mislow
Princeton University
PRINCIPLES OF MODERN
HETEROCYCLIC CHEMISTRY
Leo A. Paquette
The Ohio State University
STRUCTURE DETERMINATION
Peter Yates
University ofToronto
Second Edition
ORGANIC REACTION
MECHANISMS
AN INTRODUCTION
ROMLD BRESLOW
Columbia university
W. A. BENJAMIN, INC. New York
19 6 9
ORGANIC REACTION MECHANISMS: AN INTRODUCTION
Second Edition
Copyright © 1969 by W. A. Benjamin, Inc.
All rights reserved
Standard Book Numbers: 8053-1252-8 (Cloth)
8053-1253-6 (Paper)
Library of Congress Catalog Card Number 73-80663
Manufactured in the United States of America
12345K32109
The manuscript was put into production on January 13, 1969;
this volume was published on September 5, 1969
W. A. BENJAMIN, INC.. New York, New York 10016
EDITOR'S FOREWORD
undergraduate education in chemistry is in the midst of a ma-
jor revolution. Sophisticated material, including extensive treat-
ments of current research problems, is increasingly being intro-
duced into college chemistry courses. In organic chemistry, this
trend is apparent in the new "elementary" textbooks. However,
it has become clear that a single text, no matter how sophisticated,
is not the best medium for presenting glimpses of advanced mate-
A
rial in addition to the necessary basic chemistry. spirit of critical
evaluation of the evidence is essential in an advanced presentation,
while "basic" material must apparently be presented in a relatively
dogmatic fashion.
Accordingly, we have instituted a series of short monographs in-
tended as supplements to a first-year organic text; they may, of
course, be used either concurrently or subsequently. It is our hope
that teachers of beginning organic chemistry courses will supple-
ment the usual text with one or more of these intermediate level
monographs and that they may find use in secondary courses as
well. In general, the books are designed to be read independently
by the interested student and to lead him into the current research
literature. It is hoped that they will serve their intended educa-
tional purpose and will help the student to recognize organic chem-
istry as the vital and exciting field it is.
VI m EDITOR'S FOREWORD
We welcome any comments or suggestions about the series.
Ronald Breslow
New York, New York
December, 1964
-PREFACE TO THE FIRST EDITION
it is generally agreed that some study of organic reaction
mechanisms should be part of undergraduate organic chemical
training. There are several good reasons for this trend: (1) an
elementary grasp of how reactions occur is a great help in remem-
bering the factual data which constitute the bulk of an elementary
organic chemistry course; (2) an understanding of reaction mech-
anisms serves as a guide in the design of synthetic sequences; (3)
the investigation of organic reaction mechanisms is one of the most
active areas of current chemical research, and students should at
least be made aware of the existence of this branch of the science;
(4) a study of the type of evidence which is used to establish
reaction mechanisms introduces the student to a rigorous and
stimulating style ofthought andinduces him tobe critical in evaluat-
ing the significance of scientific evidence.
Most modern elementary textbooks introduce students to the
ideas of reaction mechanisms, and they use mechanistic outlines
in describing reactions. However, only in advanced monographs
such as Gould's Mechanism and Structure in Organic Chemistry
or Hine's Physical Organic Chemistry are unified outlines of the
field of organic reaction mechanisms presented, together with a
critical examination of the evidence for proposed mechanisms.
In the course of teaching undergraduates the author has long felt
vii
Viii m PREFACE TO THE FIRST EDITION
the need of a brief introductory book in this area; the present
volume is an attempt to fill this need. It is hoped that the book
can be read independently by undergraduates who are enrolled in
a good course in elementary organic chemistry. It should also
be useful in intermediate level courses and for advanced students
whose training in this area of organic chemistry was not up to
current standards.
In order to solve the problem of providing an introductory
treatment and at the same time indicating the current state of re-
search on mechanisms, I have adopted the device of associating a
special topic with each chapter of the book. While the chapters
are general introductions, each special topic deals with an area of
current research interest in some detail. General references follow
the chapters, but the special topics have footnotes to lead the
reader directly to the current research literature. Tables of
quantitative data are provided in both chapters and special topics
when they seem useful; organic chemistry is still far from being a
mathematical science, but the inclusion of a discussion of partial
rate factors and the a+-p relationship in aromatic substitution, for
instance, indicates to the student one direction in which the science
will certainly grow.
The first chapter on bonding and the second one on methods for
determining reaction mechanisms establish the framework for the
discussion which follows; each of these chapters is followed by a
special topic which further illustrates the chapter material in terms
of current research. The remaining five chapters,1 with their spe-
cial topics, take up specific classes of reactions and discuss their
mechanisms. The criteria used to select these classes of reactions
are (1) the reactions are important in synthetic organic chemistry,
and (2) a fair amount is known about their mechanisms. Even
so, some important reaction types have been neglected (e.g.,
catalytic hydrogenation, electrophilic aliphatic substitution, photo-
chemical reactions) because of the desire to keep the size and price
of this book attractive to its potential readers. However, it is
hoped that the choice of topics made will indicate both the scope
and depth of current mechanistic theories.
A number of people have read this manuscript at various stages
of its preparation, and it is a pleasure to be able to acknowledge
1There are six remaining chapters in the second edition.