Molecular Orbitals and Organic Chemical Reactions

by Fleming, Ian

• ISBN13: 9780470746592
• ISBN10: 0470746599
• Edition: 1st
• Format: Paperback
• Copyright: 2009-12-21
• Publisher: Wiley

Summary

Molecular orbital theory is used by chemists to describe the arrangement of electrons in chemical structures. It is also a theory capable of giving some insight into the forces involved in the making and breaking of chemical bondsthe chemical reactions that are often the focus of an organic chemist's interest. Organic chemists with a serious interest in understanding and explaining their work usually express their ideas in molecular orbital terms, so much so that it is now an essential component of every organic chemist's skills to have some acquaintance with molecular orbital theory.Molecular Orbitals and Organic Chemical Reactions is both a simplified account of molecular orbital theory and a review of its applications in organic chemistry; it provides a basic introduction to the subject and a wealth of illustrative examples. In this book molecular orbital theory is presented in a much simplified, and entirely non-mathematical language, accessible to every organic chemist, whether student or research worker, whether mathematically competent or not. Topics covered include:Molecular Orbital Theory Molecular Orbitals and the Structures of Organic Molecules Chemical Reactions How Far and How Fast Ionic Reactions Reactivity Ionic Reactions Stereochemistry Pericyclic Reactions Radical Reactions Photochemical Reactions Molecular Orbitals and Organic Chemical Reactions: An Introduction is an invaluable first textbook on this important subject for students of organic, physical organic and computational chemistry.

Author Biography

Professor Ian Fleming, Department of Chemistry, University of Cambridge
Ian Fleming is an Emeritus Professor in the Department of Chemistry in the University of Cambridge, and an Emeritus Fellow of Pembroke College. He is the author of five textbooks: Spectroscopic Methods in Organic Chemistry (McGraw Hill, now in its 6th edition), Spectroscopic Problems in Organic Chemistry (McGraw Hill); Selected Organic Syntheses (Wiley), Frontier Orbitals and Organic Chemical Reactions (Wiley) and Pericyclic Reactions (OUP Oxford Chemistry Primer series).

Table of Contents

Preface	p. xi
Molecular Orbital Theory	p. 1
The Atomic Orbitals of a Hydrogen Atom	p. 1
Molecules made from Hydrogen Atoms	p. 2
The H2 Molecule	p. 2
The H3 Molecule	p. 7
The H4 æMoleculeÆ	p. 8
C-H and C-C Bonds	p. 9
The Atomic Orbitals of a Carbon Atom	p. 9
Methane	p. 12
Methylene	p. 13
Hybridisation	p. 15
C-C ¿ Bonds and ¿ Bonds: Ethane	p. 18
C=C ¿ Bonds: Ethylene	p. 20
Conjugation-Hückel Theory	p. 22
The Allyl System	p. 22
Butadiene	p. 28
Longer Conjugated Systems	p. 31
Aromaticity	p. 32
Aromatic Systems	p. 32
Antiaromatic Systems	p. 34
The Cyclopentadienyl Anion and Cation	p. 37
Homoaromaticity	p. 37
Spiro Conjugation	p. 38
Strained ¿ Bonds-Cyclopropanes and Cyclobutanes	p. 39
Cyclopropanes	p. 39
Cyclobutanes	p. 42
Heteronuclear Bonds, C-M, C-X and C=O	p. 42
Atomic orbital energies and electronegativity	p. 43
C-X ¿ Bonds	p. 43
C-M ¿ Bonds	p. 47
C=O ¿ Bonds	p. 49
Heterocyclic Aromatic Systems	p. 51
The Tau Bond Model	p. 52
Spectroscopic Methods	p. 53
Ultraviolet Spectroscopy	p. 53
Photoelectron Spectroscopy	p. 54
Nuclear Magnetic Resonance Spectroscopy	p. 55
Electron Spin Resonance Spectroscopy	p. 56
Exercises	p. 57
The Structures of Organic Molecules	p. 59
The Effects of ¿ Conjugation	p. 59
A Notation for Substituents	p. 59
The Effect of Substituents on the Stability of Alkenes	p. 60
The Effect of Substituents on the Stability of Carbocations	p. 65
The Effect of Substituents on the Stability of Carbanions	p. 66
The Effect of Substituents on the Stability of Radicals	p. 67
Energy-Raising Conjugation	p. 69
¿ Conjugation-Hyperconjugation	p. 69
C-H and C-C Hyperconjugation	p. 70
C-M Hyperconjugation	p. 74
Negative Hyperconjugation	p. 76
The Configurations and Conformations of Molecules	p. 81
Restricted Rotation in ¿-Conjugated Systems	p. 82
Preferred Conformations from Conjugation in the ¿ Framework	p. 89
Other Noncovalent Interactions	p. 90
The Hydrogen Bond	p. 90
Hypervalency	p. 92
Polar Interactions, and van der Waals and other Weak Interactions	p. 93
Exercises	p. 95
Chemical Reactions-How Far and How Fast	p. 97
Factors Affecting the Position of an Equilibrium	p. 97
The Principle of Hard and Soft Acids and Bases (HSAB)	p. 97
Transition Structures	p. 103
The Perturbation Theory of Reactivity	p. 104
The Salem-Klopman Equation	p. 106
Hard and Soft Nucleophiles and Electrophiles	p. 109
Other Factors Affecting Chemical Reactivity	p. 110
Ionic Reactions-Reactivity	p. 111
Single Electron Transfer (SET) in Ionic Reactions	p. 111
Nucleophilicity	p. 114
Heteroatom Nucleophiles	p. 114
Solvent Effects	p. 118
Alkene Nucleophiles	p. 118
The ¿-Effect	p. 119
Ambident Nucleophiles	p. 121
Thiocyanate Ion, Cyanide Ion and Nitrite Ion (and the Nitronium Cation)	p. 121
Enolate Ions	p. 124
Allyl Anions	p. 125
Aromatic Electrophilic Substitution	p. 129
Electrophilicity	p. 134
Trigonal Electrophiles	p. 134
Tetrahedral Electrophiles	p. 136
Hard and Soft Electrophiles	p. 137
Ambident Electrophiles	p. 137
Aromatic Electrophiles	p. 138
Aliphatic Electrophiles	p. 140
Carbenes	p. 147
Nucleophilic Carbenes	p. 148
Electrophilic Carbenes	p. 149
Aromatic Carbenes	p. 149
Exercises	p. 151
Ionic Reactions-Stereochemistry	p. 153
The Stereochemistry of the Fundamental Organic Reactions	p. 154
Substitution at a Saturated Carbon	p. 154
Elimination Reactions	p. 156
Nucleophilic and Electrophilic Attack on a ¿ Bond	p. 158
The Stereochemistry of Substitution at Trigonal Carbon	p. 165
Diastereoselectivity	p. 167
Nucleophilic Attack on a Double Bond with Diastereotopic Faces	p. 169
Nucleophilic and Electrophilic Attack on Cycloalkenes	p. 175
Electrophilic Attack on Open-Chain Double Bonds with Diastereotopic Faces	p. 178
Diastereoselective Nucleophilic and Electrophilic Attack on Double Bonds Free of Steric Effects	p. 182
Exercises	p. 183
Thermal Pericyclic Reactions	p. 185
The Four Classes of Pericyclic Reactions	p. 186
Evidence for the Concertedness of Bond Making and Breaking	p. 188
Symmetry-Allowed and Symmetry-Forbidden Reactions	p. 190
The Woodward-Hoffmann Rules-Class by Class	p. 190
The Generalised Woodward-Hoffmann Rule	p. 200
Explanations for the Woodward-Hoffmann Rules	p. 214
The Aromatic Transition Structure	p. 215
Frontier Orbitals	p. 215
Correlation Diagrams	p. 216
Secondary Effects	p. 221
The Energies and Coefficients of the Frontier Orbitals of Alkenes and Dienes	p. 222
Diels-Alder Reactions	p. 224
1,3-Dipolar Cycloadditions	p. 242
Other Cycloadditions	p. 252
Other Pericyclic Reactions	p. 259
Periselectivity	p. 263
Torquoselectivity	p. 267
Exercises	p. 270
Radical Reactions	p. 275
Nucleophilic and Electrophilic Radicals	p. 275
The Abstraction of Hydrogen and Halogen Atoms	p. 277
The Effect of the Structure of the Radical	p. 277
The Effect of the Structure of the Hydrogen or Halogen Source	p. 278
The Addition of Radicals to ¿ Bonds	p. 279
Attack on Substituted Alkenes	p. 279
Attack on Substituted Aromatic Rings	p. 282
Synthetic Applications of the Chemoselectivity of Radicals	p. 286
Stereochemistry in some Radical Reactions	p. 287
Ambident Radicals	p. 290
Neutral Ambident Radicals	p. 290
Charged Ambident Radicals	p. 291
Radical Coupling	p. 295
Exercises	p. 296
Photochemical Reactions	p. 299
Photochemical Reactions in General	p. 299
Photochemical Ionic Reactions	p. 301
Aromatic Nucleophilic Substitution	p. 301
Aromatic Electrophilic Substitution	p. 302
Aromatic Side-Chain Reactivity	p. 303
Photochemical Pericyclic Reactions and Related Stepwise Reactions	p. 304
The Photochemical Woodward-Hoffmann Rule	p. 304
Regioselectivity of Photocycloadditions	p. 307
Other Kinds of Selectivity in Pericyclic and Related Photochemical Reactions	p. 319
Photochemically Induced Radical Reactions	p. 321
Chemiluminescence	p. 323
Exercises	p. 324
References	p. 327
Index	p. 331
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