Structure and Reactivity in Organic Chemistry

by Moloney, Mark G.

• ISBN13: 9781405114516
• ISBN10: 1405114517
• Edition: 1st
• Format: Paperback
• Copyright: 2008-04-28
• Publisher: Wiley-Blackwell

Summary

The jump from an understanding of organic chemistry at lower undergraduate level to that required at postgraduate level or in industry can be difficult. Many advanced textbooks contain a level of detail which can obscure the essential mechanistic framework that unites the huge range of facts of organic chemistry. Understanding this underlying order is essential in any advanced study or application of organic chemistry. Structure and Reactivity in Organic Chemistry aims to bridge that gap. The text opens with a short overview of the way chemists understand chemical structure, and how that understanding is essential in developing a good knowledge of chemical reactivity and mechanism. The remainder of the text presents a mechanistic classification of modern organic chemistry, developed in the context of synthetic organic chemistry and exemplified by reference to stereoselective synthesis and protecting group chemistry. This approach is intended to illustrate the importance and value of a good grasp of organic reaction mechanisms, which is a prerequisite for a broader understanding of organic chemistry. Written by an expert educator with a sound understanding of the needs of different audiences, the subject is presented with clarity and precision, and in a highly practical manner. It is relevant to undergraduates, postgraduates and industrial organic chemists.

Author Biography

Mark G. Moloney
Chemistry Research Laboratory, University of Oxford and St Peter's College, Oxford.

Table of Contents

Preface	p. xi
Bonding	p. 1
Atomic structure	p. 1
The chemical bond	p. 1
The periodic table	p. 1
Valence electrons	p. 3
Lewis structures	p. 3
Conventions for drawing structures	p. 5
Atomic orbital theory	p. 6
Molecular orbital theory	p. 7
Covalent bonding	p. 10
Bonding in hydrocarbons	p. 11
Bonding in compounds containing heteroatoms	p. 12
Bonding in common functional groups	p. 12
Electronic effects	p. 14
Steric effects	p. 18
Stereoelectronic effects	p. 18
Double bond equivalents	p. 20
Structure	p. 21
Configuration	p. 21
Geometrical isomerism	p. 22
Optical isomerism	p. 23
Representations of stereoisomers	p. 25
Molecules with one stereogenic centre	p. 27
Molecules with more than one stereogenic centre	p. 27
Molecules with more than one stereogenic centre which are not optically active	p. 28
Optically active molecules without stereogenic centres: molecular asymmetry	p. 29
Asymmetric heteroatoms	p. 30
Conformation	p. 31
Representation of conformers	p. 31
Open-chain compounds	p. 31
Ring compounds	p. 33
Summary of stereochemical relationships	p. 39
Naturally occurring chiral compounds	p. 39
Asymmetric synthesis	p. 41
Enantioselective synthesis	p. 41
Diastereoselective synthesis	p. 43
Methods for the determination of enantiomeric purity	p. 43
Reactivity	p. 47
Thermodynamics	p. 47
Gibbs free energy	p. 47
Enthalpy	p. 48
Entropy	p. 50
Chemical equilibrium	p. 52
Kinetics	p. 54
Rates of reaction	p. 54
Reactions with competing steps	p. 57
Overcoming activation energy barriers	p. 58
Reaction mechanism	p. 60
What is reactivity?	p. 60
Lewis acids and bases: 'philicity'	p. 60
Polarisability effects: Hard-Soft Acid-Base theory	p. 61
Curly ('curved') arrows	p. 63
Classes of reaction mechanism	p. 66
Polar mechanisms	p. 66
Radical mechanisms	p. 67
Pericyclic mechanisms	p. 67
Ligand coupling reaction mechanisms	p. 67
Principle of microscopic reversibility	p. 68
Selectivity of reactions	p. 69
Solvents in organic chemistry	p. 71
Redox reactions in organic chemistry	p. 72
Intermediates	p. 77
Carbocations	p. 77
Structure	p. 77
Factors stabilising carbocations	p. 77
Generation of carbocations	p. 81
Rearrangements of carbocations	p. 82
Carbanions	p. 82
Structure	p. 82
Carbanions derived from simple alkanes	p. 84
Factors stabilising carbanions	p. 85
Carbanions with covalent character	p. 88
Grignard reagents (RMgX)	p. 88
Organolithium reagents (RLi)	p. 89
Organocadmium reagents	p. 89
Radicals	p. 90
Structure	p. 90
Factors stabilising radicals	p. 90
Generation of radicals	p. 92
Carbenes	p. 94
Stability and structure	p. 94
Generation of carbenes	p. 95
Benzynes	p. 96
Stability and structure	p. 96
Generation of benzynes	p. 97
Ketenes	p. 98
Stability and structure	p. 98
Generation of ketenes	p. 98
Acidity and Basicity	p. 99
Lowry-Bronsted Acid-Base theory	p. 99
Organic acidity	p. 100
Organic acids	p. 100
Organic basicity	p. 111
Organic bases	p. 112
Nucleophilic Substitution	p. 117
The S[subscript N]1 reaction	p. 117
Factors affecting the S[subscript N]1 reaction	p. 118
The S[subscript N]2 reaction	p. 123
Factors enhancing the S[subscript N]2 reaction	p. 124
Synthetic applications of nucleophilic substitution reactions	p. 128
Protecting-group chemistry	p. 128
Stereocontrolled alkylation reactions	p. 131
Addition Reactions	p. 139
Electrophilic addition reactions	p. 139
Addition of halogens	p. 139
Addition of hydrogen halides	p. 141
Addition of hydrogen halides to conjugated dienes	p. 143
Addition of diborane (hydroboration)	p. 143
Addition of hydrogen	p. 147
Addition of oxygen	p. 148
Addition of carbon	p. 153
Nucleophilic addition reactions	p. 153
Irreversible nucleophilic addition	p. 154
Irreversible nucleophilic conjugate addition	p. 159
Reversible nucleophilic addition	p. 160
Additions to electron-deficient alkenes	p. 165
Additions of ketenes	p. 165
Synthetic applications	p. 166
Elimination Reactions	p. 169
Eliminations	p. 169
E[subscript 1] reactions	p. 169
E[subscript 1]CB reactions	p. 169
E[subscript 2] reactions	p. 170
Eliminations leading to isomeric products	p. 173
Competition between substitution and elimination	p. 175
The leaving group	p. 176
Oxidation processes	p. 178
[alpha]-Eliminations leading to carbenes and nitrenes	p. 181
Eliminations of phosphorus	p. 182
Eliminations of sulfur and selenium	p. 182
Eliminations in protecting-group chemistry	p. 184
Aromatic Substitution	p. 189
Aromaticity	p. 189
Benzene	p. 189
Heteroaromatics	p. 189
Reactions	p. 191
Acidity and basicity	p. 191
Electrophilic aromatic substitution	p. 191
Orientation effects in electrophilic aromatic substitution (S[subscript E]Ar)	p. 202
o-Lithiation	p. 205
Nucleophilic aromatic substitution	p. 206
Arene chromium tricarbonyl complexes	p. 211
Sequential Addition and Elimination Reactions	p. 213
Addition-elimination reactions	p. 213
Addition of hydride	p. 220
Addition of heteroatom nucleophiles	p. 221
Addition of carbon nucleophiles	p. 222
Addition of phosphorus nucleophiles	p. 225
Addition-elimination reactions in conjugated systems	p. 230
Addition-elimination reactions in heterocyclic systems	p. 230
Addition-elimination reactions in ring-closing metathesis	p. 231
Addition-elimination reactions in deprotections	p. 234
Radical Reactions	p. 237
Generation	p. 237
Reactions	p. 237
Termination	p. 237
Propagation	p. 238
Substitution	p. 239
Addition reactions	p. 242
Fragmentation	p. 249
Rearrangement	p. 250
Synthetic utility	p. 255
Ligand Coupling Reactions	p. 263
Palladium-mediated couplings	p. 263
Palladium-mediated coupling processes	p. 264
Heck coupling	p. 271
Allylic coupling processes	p. 273
Ligand coupling processes mediated by other elements	p. 275
Copper	p. 276
Magnesium	p. 277
Lead	p. 279
Pericyclic Reactions	p. 283
Molecular orbitals and the FMO approach	p. 283
Pericyclic reactions	p. 284
Electrocyclic reactions	p. 285
Cycloaddition reactions	p. 287
Sigmatropic reactions	p. 293
Synthetic applications of pericyclic reactions	p. 296
Index	p. 303
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