The Alkenes: Volume 1 (1964)

1311 Pages·1964·28.6 MB·English

The Chemistry of Alkenes
Edited by Saul Patai
Copyright 0 1964 John Wiley & Sons Ltd. All Rights Reserved.
The chemistry of
Edited by
SAUL PATAI
The Hebrew Uniuersily
Jerusalem, Israel
1964
INTERSCIENCE PUBLISHERS
a division of John Wiley & Sons
LONDOPI' - YORK - SYDNEY
KEW
Copyright 0 1964John Wiley & Sons Ltd. All
Rights Reserved. No part of this publication
may be reproduced, stored in a retrieval system,
or transmitted, in any form or by any means
electronic, mechanical photocopying, recording
or otherwise, without the prior written permis-
sion of the Copyright owner.
Library of Congress Catalog Card Number 64-252 18
ISBN 0 470 66930 6
Reprinted 1972
Printctl in Great Britain by Unwin Urotlicrs 1,imitc.d
Tlie Grcsham Press, Old IVoking, Surrey
:\ member or tlic Staples Printing Group
Contribwti ng authors
John 1. G. Cadogan St. Salvator’s College, University of St.
Andrews, Scotland
Michael Cais Technion - Israel Institute of Technology,
Haifa, Israel
C. A. Coulson Mathematics Institute, University of Oxford,
England
Thomas I. Crowell University of Virginia, Charlottesville,
Virginia, U.S.A.
Robert H. DeWolfe University of California at Santa Barbara,
USA.
Herbert Fischer Max Planck Institute, Heidelberg, Germany
Rudolf Grashey Institute for Organic Chemistry of the
University of Munich, Germany
Rolf Huisgen Institute for Organic Chemistry of the
University of Munich, Germany
Edward J. Kuchar Analytical Services, Oiin Mathieson Chemi-
cal Corporation, New Haven, Connecticut,
U.S.A.
Richard N. Lace:# E.P. Research Cei-itre, Siiiibiiiy-oii-Thames,
Middlesex, England
Allan Maccoll University College, University of London,
England
Kenneth Mackenzie Bedford College, University of London,
England
Saul Patai The Hebrew University, Jerusalem, Israel
Michael J. Perkins King’s College, University of London,
EEgland
Zvi Rappoport The Hebrew University, Jerusalem, Israel
Jurgen Sauer Institute for Organic Chemistry of the
University of Munich, Germany
William Saunders, Jr. University of Rochester, New York, USA.
H.
E. Theal Stewart Queen’s College, University of St. Andrews,
Dundee, Scotland
William G. Young University of California at Los Angeles,
U.S.A.
V
Foreword
The aim of this book is to prcsent an up-to-clatc dissertation on the
chemistry of the carbon-carbon dolihle bond in all its aspects. An
encyclopaedic coverage of all known reactions, data, or measurements
relating to the topics covered in the various chapters was not intended;
indeed the authors were asked to refrain from doing so. Rather, the
emphasis was put on comparative and critical discussion of the sub-
jects, addressed to the advanced student and research chemist. It
was attempted to include far as possible all the relevant information
as
on the recent advances regarding the theory and practice of the
subject, stressing especially the theoretical, physical and mechanistical
Iii this it may possibly be argued that both
rnp--; -n.b”L:-plnL”o . .-vs:,l*c-,l- w GF
directions of ?L reversible reaction, say addition and elimination,
should have been discussed together in the same chapter. It was
attempted to prepare such a plan for the contents of this book, but it
soon became clear that it could not be carried out to its logical
conclusion in a multi-authored treatise. The close interconnection
of the :Jarious parts of the subject would make it possibly more suitable
for unified treatment by a single author, if one could be found
possessing the qualifications of encyclopaedicai knowledge and
unlimited time for writing. Therefore, while aware of the limitations
of the present plan, this had to be adopted, giving each author the
task of writing a more or less defined account of a single aspect of the
chemistry of alkenes.
The treatment of the material was limited to the reactions in which
the carbon-carbon double bond is either formed or is the site of
reaction, and reactions occurring in parts of the molecule remote from
the C=C bond are discussed only if they are influenced by the latter.
This puts the emphasis on the C=C bond as afunctional group. Again
it may be argued that the treatment of a single functional group is not
in accordance with the most modern principles, since mechanistic
similarities unite the reactions of differcnt functional groups, as for
instance the nucleophilic reactions on an activated C=C bond and on
a carbonyl carbon atom. Still, organic chemistry is in most places
taught according to functional groups and the mnemotechnic advan-
tages of this division are so great that it will probably not be displaced
vii
...
Vlll Foreword
for many decades yet to come. We hope that a series of advanced
treatises on the chemistry of the functional groups will be a useful and
valuable addition to the literature of organic chemistry, and the present
volume is the first in this planned series.
There are two obvious gaps in the structure of the book. The
chapters on ‘Electrophilic Attacks on Alkenes ’ and on ‘Biochemical
Formation and Reactions of Alkenes’ were promised but were not
delivered. After several months waiting, what is telieved by the
editor and the publisher to be the lesser evil was chosen and it was
decided to publish the book in its present form, with these cha-pters
missing, further delay would have rendered the text of the other
as
chapters out of date.
I wish to thank Dr. Arnold Weissberger who encouraged me tn
undertake the task of editing this book, and who was always ready to
help me with friendly advice and helpful suggestions. My thanks are
also due to the staff of the publisher’s editorial ofice in London, who
took upon themselves additional work and trouble to overcome the
difficulties of coping with an editor residing several thousand kilo-
meters distant from their office. Finally, it is a pleasure to acknowl-
edge the help given to me in many ways by my senior pupils and
younger colleagues, especially by Dr. 2. Rappoport and by Mr. M.
Michmann, who also undertook the arduous task of preparing the
indexes.
Jerusalem, May SAULP ATAI
1964
contents
1. Wave mechanics and the alkene bond 1
C. A. Coulson and E. Theal Stewart
2. Elimination reactions in solution 149
William H. Saunders, Jr.
3. Olefin-forming eliminations in the gas phase 203
Allan Maccoll
4. Aikene-forming condensation reactions 24 1
Thomas I. Crowell
5. Detection and determination of the alkenes 27 1
Edward J. ICuchar
6. Alkene complexes of same transition metals 335
Michael Cais
7. Alkene rearrangements 38 7
Kenneth Mackenzie
8. Nucleophilic attacks on carbon-carbon double bonds 469
Saul Patai and Zvi Rappoport
9. Reactions of alkenes with radicals and carbenes 585
John I. G. Cadogan and Michael J. Perkins
10. Allylic reactions 68 1
Robert H. DeWolfe and William G. Young
11, Cycloaddition reactions of alkenes 739
Rolf Huisgen, Rudolf Grashey and Jiirgen Sauer
12. Conjugated dienes 955
Michael Cais
13. Cumulenes 1025
Herbert Fischcr
14. Ketenes 1161
Richard N. Lacey
Author in dex 1229
Subject index 1291
ix
The Chemistry of Alkenes
Edited by Saul Patai
Copyright 0 1964 John Wiley & Sons Ltd. All Rights Reserved.
1
CHAPTER
awe -mechanics and the
ene bon
C. A. COULSON
Mathematical Institute, University of Oxford, Englaird
and
E. THEASLT EWART
Queen’s College, Dundee, Scotland
.
I. INTRODUCTION 2
11. HYDROGEN-LVIJKAVEE FUNCTION.S 6
A. Energy Levels . 6
B. The Ground State of the Hydrogen Atom . 7
C. The Schrhdinger Energy Equation . 9
D. Atomic Wave Functions . 11
E. Quantum Numbers . 15
F. Pictorial Representation of Atomic Orbitals . 16
G. Nodes . 22
H. Degeneracy . 22
I. Orthogonality . 24
111. APPROXIMAWTEA VEF UNCTIONFOSR MANY-ELECTRSOYNS TEMS2 4
A. Energies Corresponding to Approximate Wave Functions 24
B. The Variation Principle for Ground-state Wave Functions 27
C. The Hamiltonian Operator for the Hydrogen Molecule . 27
D. Product Wave Functions . 29
.
IV. THEG ROUNDST ATEO F THE HYDROGMENO LECULE 32
A. Valence-bond Wave Functions . 32
B. The Overlap Integral . 38
C. Molecular-orbital Wave Function . 39
D. Configuration Interaction . 42
E. The Scale Parameter (Orbital Exponent) . 43
F. Electron Density . 44
V. ANTISYMMETRIWZEADV EF UNCTION.S 46
A. Electron Spin . 46
.
B. The Pauli Principle 48
C. Determinantal Wave Functions . 51
D. Spin States . 53
1
C. A. Coulson and E. T. Stewart
. .
VI. LOW-ENERGSYT ATESO F THE HYDROCZMNO LECULE 57
A. Atomic-orbital Bases . . 57
. .
B. Molecular-orbital Wave Functions 59
C. The Variation Principle for Excited-state Wave Functions 62
D. Valence-bond Wave Functions . . 63
E. Linear Variation Functions . 64
F. Configuration Interaction in the Ground State . . 67
VII. MOLECULAR-ORBIWTAALV EF UNCTIOFNORS DIATOMIMC OLE-
. .
CULES 69
A. Orbital Energies and ' One-electron' Hamiltonian Operators 69
. .
B. Linear Combinations of Atomic Orbitals
C. Diatomic Molecules . (LCAO) . 7784
D. Fluorine . . 80
.
E. Bond Order . 85
F. Hydrogen Fluoride . . 87
VIII. MOLECULAR-ORBIWTAALV EF UNCTIONFOSR SIMPLEO RGANIC
MOLECULES. . 88
A. Acetylene. . 88
B. Bond Orbitals . . 91
C. Hybridization . . 93
D. Ethylene . . 95
E. Bent-bond Orbitals . . 98
F. Methane . . 102
G. Atomic Orbitals in Molecular Wave Functions . 104
IX. THEV ELECTRONH YPOTHESX.S . 106
A. n-Electroil Energy . . 106
B. r-Electron Wave Functions . 108
x. THEH UCKEALP PROXIhlATION . . 110
A. Ethylene . . 110
.
B. Buta-1,3-diene . 116
C. Higher Polyenes . . 122
D. Delocalization Energy . . 123
E. Antisymmetrized Wave Functions . . 127
SPECTRA . . 129
XT.
A. Ethylene and the Higher Polyenes . . 129
B. Ethylene: Rotation Around the Double Bond . 135
C. Alkylation of Ethylenes : Substituted Alkenes . 139
XII. REFERENCE.S . 146
I. INTRODUCTION
There will be very few readers of this chapter who will not at first
question the relevance of a great deal of the material in its earlier
sections. It is not until section VIII that we venture to discuss an
alkene molecule, and this may well seem excessively cautious at a
time when all but the most sheltered students of elementary organic
I. Wave Mechanics and the Alkene Bond 3
chemistry are introduced to terms Eke ‘orbital,’ ‘hybridization’, and
‘overlap’ almost as soon as they have learnt the structural formulae
of the simplest hydrocarbons.
But of COKS~ a wzve-mechanical descriprion of bonding in organic
molecules requires far more than just the assimilation of a little
quantum-chemical terminology into the language of classical organic
chemistry. We would do wrong not to make it clear at the outset
that, from the wave-mechanical point of view, the 0-m systems with
which this book is concerned are by no means as straightforward as is
often suggested. Any worth-while study of the bonding in an alkene
or polyene molecule (or, indeed, any polyatomic molecule) demands,
quite inescapably, a prior understanding of the quantum chemistry of
much simpler molecules. We have tried to provide a basis for this
understanding in sections I1 to VII, our aim in these sections being to
give an account which readers whose interests are in other fields of
chemistry will find neither overtaxingly difficult nor unrewardingly
elementary.
Because most other procedures lead to computational excesses,
molecular ~4raveh nctions are almost invariably compounded from
atomic wave functions, which in turn are formulated by analogy with
:he wave functions for the one-electron series H, He +,L i2+ ,B e3 ..
+ y..
So in section I1 we discuss ‘hydrogen-like’ atomic wave functions and
the energy levels to which they are related by the Schrodinger wave
equation.
Wave functions for systems of more than one electron must always
be approxima;e in some degree, and the analytical forms in which
they are expressed can never be unique. It is mainly for this reason
that the theoretical study of alkene niolecules must be preceded by a
study of much simpler systcms, in which it is comparatively easy to
demonstrate the nature and the qlrantitative importance of the
approximations. In section I11 we outline some of the principles
involved in obtaining approximate wave functions, and in section IV
we apply these principles to the ground state of the hydrogen molecule,
the wave functions for which have long been used as prototypes for
the wave functions of almost all covalently bonded molecules.
In any wave function built up from two or more spatial orbitals it
is necessary to take into account electron spin and the Pauli principle,
which are extraneous to Schrodinger wave mechanics, and which have
accordingly to be dealt with somewhat arbitrarily. Where results
of wide applicability are required, the arbitrary procedure is most
conveniently formulated in term of angular rtlomentum; but, to
4 C. A. Coulson and E. Stewart
T.
avoid embarking on an exposition which, though perfectly straight-
forward, is lengthy and not essential for our purposes, we give in
section V an alternative formulation-admittedly restricted-in
terms ~fclectronicen ergy. In this we make use of the fairly detailed
energy relations derived in section IV.
It is not always appreciated that, when the ground-state and the
lower-excited-state wave functions for a molecule are built up from
the same set of ground-state atomic orbitals, the molecular wave
functions for the excited states are normally far less satisfactory than
that for the ground state. This is an important point, so we have
gone out of our way to emphasize it in section VI. In the same
section we discuss linear variation functions, partly to illustrate the
close resemblance between molecular-orbital and valence-bond wave
functions, and partly to provide a background for the subsequent
description of wave functions based on linear combinations of atomic
orbitals.
In sections VII and VIII, after examining the restrictions on the
linear combination of atomic orbitals which result from differences in
symmetry or energy, we describe wave fumtions for the five molecules
F,, HF, C2H4, CH4 (taken in order of increasing geometrical
C2H2,
complexity). In a monograph on the alkenes the preliminary study
of the two diatomic molecules may seem an intrusion, but it enor-
mously simplifies the later description of bonding in polyatomic
organic molecules. In consequence of the developm.ent of electronic
computing resources, much precise calculation on linear molecules,
especially diatomic molecules, has been carried out in recent years.
We have discussed this important work in some detail, partly because
(so far as we know) no simple account of it has been given elsewhere,
but mainly because most of the results are of quite general application
and are by no means restricted to diatomic molecules, or even to
linear molecules. In selecting and HF for detailed comparison
F2
with our purpose has been to draw attention to some of the
C2H2
quantum-chemical resemblances between inorganic and organic
molecules.
The remaining sections of the chapter are devoted to various
aspects of the quantum chemistry of n-electron systems. In these
sections we have tried to provide the background necessary for a
perceptive study of the literature; we have made no attempt to review
or catalogue the enormous amount of work published during the past
thirty years. After a critical examination of the concept of rr-electron
energy in section IX, we explain the Huckel approximation in section