Stereochemistry

by Morris, David G.

• ISBN13: 9780854046027
• ISBN10: 085404602X
• Format: Paperback
• Copyright: 2002-01-01
• Publisher: Royal Society of Chemistry

Summary

Stereochemistry is defined as the study of the three-dimensional structure of molecules. Stereochemical considerations are important in both isomerism and studies of the mechanisms of chemical reactions. Implicit in a mechanism is the stereochemistry of the reaction: in other words, the relative three-dimensional orientation of the reacting particles at any time in the reaction. Concentrating on organic chemistry, early chapters deal mainly with definitions of terms such as chirality, enantiomers, diastereoisomers and racemization, complete with suitable examples to illustrate key concepts. Use of a polarimeter and associated definitions are described, together with two different conventions D, L and R, S for specification of configuration. Chirality without a stereogenic centre, in molecules such as allenes for example, is also covered. The distinction between conformation and configuration is developed to include assignment of configurations to di-substituted cyclohexanes and to the decalins. The conventions E, Z and Re, Si are introduced for sp2 hybridized carbons as found in alkenes and carbonyl compounds. Diastereotopic groups are discussed. Aspects of stereochemistry are explored through consideration of addition reactions to alkenes and carbonyl groups, nucleophilic substitution, and reactions (and interactions) involved in the resolution of racemic mixtures. Additional material is available on the website at www.rsc.org/tct Ideal for the needs of undergraduate chemistry students, Tutorial Chemistry Texts is a major series consisting of short, single topic or modular texts concentrating on the fundamental areas of chemistry taught in undergraduate science courses. Each book provides a concise account of the basic principles underlying a given subject, embodying an independent-learning philosophy and including worked examples.

Table of Contents

Simple Molecules: Hybridization, Conformation and Configuration	p. 1
Introduction	p. 1
Hybridization: Methane	p. 2
Hybridization: Ethene and Alkenes	p. 3
Hybridization: Ethyne	p. 5
Bonding and Anti-bonding Orbitals	p. 6
Conformation: Ethane	p. 7
Conformation of Propane and n-Butane	p. 9
Cyclohexane: Chair Conformation	p. 10
Cyclohexane: Boat Conformation	p. 12
Inversion of Cyclohexane	p. 14
Monosubstituted Cyclohexanes	p. 15
Chiral Molecules: One Stereogenic Centre	p. 19
Chirality, Enantiomers and Optical Activity	p. 19
How to Specify a Configuration	p. 23
Enantiomeric Excess, Enantiomeric Ratio	p. 27
Racemization	p. 29
Homochiral Molecules	p. 30
Molecules with Two (or More) Stereogenic Centres	p. 37
Enantiomers and Diastereoisomers	p. 37
Meso Configuration	p. 39
Erythro/Threo and Syn/Anti Configurations	p. 41
Caged Compounds with Two Stereogenic Bridgehead Carbons	p. 43
Epimers, and the Nomenclature of Bicyclic Compounds	p. 44
Separation of Enantiomers: Resolution	p. 46
Separation of Enantiomers by Chromatography	p. 48
Resolution with Enzymes	p. 49
Structure of Polypropene	p. 52
Stereochemistry of Carbon-Carbon and Carbon-Nitrogen Double Bonds	p. 60
Configuration and Relative Stability of Alkenes and Dienes	p. 60
Cyclohexene	p. 62
Carbon-Nitrogen Double Bonds	p. 63
Amides	p. 64
Cis Hydroxylation of Alkenes	p. 67
Trans Hydroxylation of Alkenes	p. 67
Addition of Bromine to Alkenes	p. 69
Hydration of Alkenes	p. 72
Chirality without Stereogenic Carbon	p. 80
Allenes and Related Molecules	p. 80
Biphenyls	p. 83
Absolute Configuration of Allenes and Biphenyls	p. 85
Hexahelicene	p. 86
Silicon, Germanium and Tin Compounds	p. 87
Amines, Ammonium Salts, Phosphorus and Arsenic Compounds	p. 88
Sulfoxides, Sulfonium Salts and Selenoxides	p. 91
Stereoisomerism in Cyclic Structures	p. 99
Cyclic Molecules, Configurational Assignment and Strain	p. 99
Cyclopropane	p. 100
Cyclobutane	p. 101
Cyclopentane	p. 102
Cyclohexanes	p. 102
Decalins	p. 111
Steroids	p. 113
Anomeric Effect	p. 114
Substitution Reactions at Saturated Carbon	p. 125
Nucleophilic Substitution	p. 125
Prochirality, Enantiotopic and Diastereotopic Groups and Faces: Use of NMR Spectroscopy in Stereochemistry	p. 139
Prochiral Molecules, Enantiotopic Groups and Faces	p. 140
Diastereotopic Compounds	p. 143
Reactivity Difference of Enantiotopic Hydrogens and in Enzyme-mediated Reactions	p. 144
Non-enzymatic Selectivity in Addition to C=O and C=C Bonds	p. 145
Stereochemical Information from NMR Spectroscopy	p. 147
Answers to Problems	p. 161
Subject Index	p. 168
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