ORGANIC CHEMISTRY SEVENTH EDITION L.G.WADE,JR
ABOUT THE AUTHOR L.G."Skip"Wade decided to be romPo Ronald M.Magid AferBrom Rice 1969.Wade went on to Harvard University.where he did research with Pro- While at Harvard,he served as the Head Teaching H.Westheimer. After completing his Ph.D.at Harvard in 1974.Dr.Wade joined the chem te.Dr.Wade dents working toward careers in allareas of hiology.chemistry.human med. icine,veterinary medicine,and environmental studies.He also authored cal education,as well a Dr Wade has been a chemisty teaches organic chemistry and pursues research interests in organic synthe Dr.Wade's interest in forensic science has led him to testify as an expert wit- ness in court cases involving drugs and firearms.and he has worked as a many years. To my students and colleagues at Whitman College
ABOUT THE AUTHOR L. G. "Skip 11 Wade decided to become a chemistry major during his sophomore year at Rice University, while taking organic chemistry from Professor Ronald M. Magid. After receiving his B.A. from Rice in 1969, Wade went on to Harvard University, where he did research with Professor James D. White. While at Harvard, he served as the Head Teaching Fellow for the organic laboratories and was strongly influenced by the teaching methods of two master educators, Professors Leonard K. Nash and Frank H. Westheimer. After completing his Ph.D. at Harvard in 1974, Dr. Wade joined the chemistry faculty at Colorado State University. Over the course of fifteen years at Colorado State, Dr. Wade taught organic chemistry to thousands of students working toward careers in all areas of biology, chemistry, human medicine, veterinary medicine, and environmental studies. He also authored research papers in organic synthesis and in chemical education, as well as eleven books reviewing current research in organic synthesis. Since 1989, Dr. Wade has been a chemistry professor at Whitman College, where he teaches organic chemistry and pursues research interests in organic synthesis and forensic chemistry. Dr. Wade received the A. E. Lange Award for Distinguished Science Teaching at Whitman in 1993. Dr. Wade's interest in forensic science has led him to testify as an expert witness in court cases involving drugs and firearms, and he has worked as a police firearms instructor, drug consultant, and boating safety officer. He also enjoys repairing and restoring old violins and bows, which he has done professionally for many years. To my students and colleagues at Whitman College
CONTENTS Preface xxii About the Author ii 1 INTRODUCTION AND REVIEW 1 1-1 The Origins of Organic Chemistry I 1-2 Principles of Atomie Structure 3 1-3 Bond Formation:The Octet Rule 6 1-4 Lewis Structures 7 1-5 Multiple Bonding 8 Summary:Common Bonding Patterns (Uncharged)9 1-9 Resonance 13 1-10 Structural Formulas 17 1-l1 Molecular Formulas and Empirical Formulas 20 1-12 Arrhenius Acids and Bases 21 1-13 Bronsted-Lowry Acids and Bases 22 4 Lewis Acids and Bases29 Chapter I Glossary 32 Study Problems 34 STRUCTURE AND PROPERTIES 2 OF ORGANIC MOLECULES 40 2-1 Wave Properties of Electrons in Orbitals 40 2-2 Molecular Orbitals 42 2-3 Pi Bonding 45 2.4 Hybridization and Molecular Shapes 46 2-5 Drawing Three-Dimensional Molecules 50 General Rules of Hybridization and Geometry 51 Bond Rotation 55 onds and Mo 212 2.130 2.14 anic Co n74 Chapter 2 Glo Study Problems 79
CONTENTS vi Preface xxii About the Author 111 1 INTRODUCTION AND REVIEW 1 1-1 The Origins of Organic Chemistry 1 1-2 Principles of Atomic Structure 3 1-3 Bond Formation: The Octet Rule 6 1-4 Lewis Structures 7 1-5 Multiple Bonding 8 Summary: Common Bonding Patterns (Uncharged) 9 1-6 Electronegativity and Bond Polarity 9 1-7 Formal Charges 10 1-8 Ionic Structures 12 Summary: Common Bonding Patterns in Organic Compounds and Ions 13 1-9 Resonance 13 1-10 Structural Formulas 17 1-11 Molecular Formulas and Empirical Formulas 20 1-12 Arrhenius Acids and Bases 21 1-13 Bronsted-Lowry Acids and Bases 22 1-14 Lewis Acids and Bases 29 Chapter 1 Glossary 32 Study Problems 34 STRUCTURE AND PROPERTIES 2 OF ORGANIC MOLECULES 40 2-1 Wave Properties of Electrons in Orbitals 40 2-2 Molecular Orbitals 42 2-3 Pi Bonding 45 2-4 Hybridization and Molecular Shapes 46 2-5 Drawing Three-Dimensional Molecules 50 2-6 General Rules of Hybridization and Geometry 51 2-7 Bond Rotation 55 2-8 Isomerism 57 2-9 Polarity of Bonds and Molecules 59 2-10 Intermolecular Forces 62 2-11 Polarity Effects on Solubilities 66 2-12 Hydrocarbons 69 2-13 Organic Compounds Containing Oxygen 72 2-14 Organic Compounds Containing Nitrogen 74 Chapter 2 Glossary 76 Study Problems 79
Contents 3 STRUCTURE AND STEREOCHEMISTRY OF ALKANES 83 3-1 Classification of Hydrocarbons(Review)83 3-2 Molecular Formulas of Alkanes 84 3-3 Nomenclature of Alkanes 85 Summary:Rules for Naming Alkanes 90 anes 93 1 s of Alkanes 9 e100 ations of Higher 3-10 Cycloalkanes 102 3-11 cis-trans Isomerism in Cycloalkanes 105 3-12 Stabilities of Cycloalkanes:Ring Strain 105 3-13 Cyclohexane Conformations 109 roblem-Soving Strategy:Drawing Chair 3-14 Conformations of Monosubstituted Cyclohexanes I13 3-15 Conformations of Disubstituted Cyclohexanes 116 Problem-Solving trateg:cis 3-16 Bicyclic Molecules 119 Chapter 3 Glossary 121 Study Problems 124 4 THE STUDY OF CHEMICAL REACTIONS 127 4-1 Introduction 127 4-2 Chlorination of Methane 127 4-3 The Free-Radical Chain Reaction 128 Key Mechanism:Free-Radical Halogenation 130 4-4 Equilibrium Constants and Free Energy 132 Enthalpy and Entropy 135 Bond-Dissociation Enthalpies 136 Enthalpy Cha Activation eeuation /39 K Temperature Dependence 4-10 Transition States 142 4-11 Rates of Multistep Reactions 144 4-12 Temperature Dependence of Halogenation 145 4-13 Selectivity in Halogenation 146 4-14 The Hammond Postulate 151 Strategy:Proposing Reaction 4-15 Radical Inhibitors 155 4-16 Reactive Intermediates 156 Summary:Reactive Intermediates 162 Chapter 4 Glossary 162 Study Problems 165
3 STRUCTURE AND STEREOCHEMISTRY OF ALKANES 83 3-1 Classification of Hydrocarbons (Review) 83 3-2 Molecular Formulas of Alkanes 84 3-3 Nomenclature of Alkanes 85 Summary: Rules for Naming Alkanes 90 3-4 Physical Properties of Alkanes 91 3-5 Uses and Sources of Alkanes 93 3-6 Reactions of Alkanes 95 3-7 Structure and Conformations of Alkanes 96 3-8 Conformations of Butane 100 3-9 Conformations of Higher Alkanes 102 3-10 Cycloalkanes 102 3-11 cis-trans Isomerism in Cycloalkanes 105 3-12 Stabilities of Cycloalkanes; Ring Strain 105 3-13 Cyclohexane Conformations 109 Problem-Solving Strategy: Drawing Chair Conformations 112 3-14 Conformations of Monosubstituted Cyclohexanes 113 3-15 Conformations ofDisubstituted Cyclohexanes 116 Problem-Solving Strategy: Recognizing cis and trans Isomers 118 3-16 Bicyclic Molecules 119 Chapter 3 Glossary 121 Study Problems 124 4 THE STUDY OF CHEMICAL REACTIONS 127 4-1 Introduction 127 4-2 Chlorination of Methane 127 4-3 The Free-Radical Chain Reaction 128 Key Mechanism: Free-Radical Halogenation 130 4-4 Equilibrium Constants and Free Energy 132 4-5 Enthalpy and Entropy 135 4-6 Bond-Dissociation Enthalpies 136 4-7 Enthalpy Changes in Chlorination 137 4-8 Kinetics and the Rate Equation 139 4-9 Activation Energy and the Temperature Dependence of Rates 141 4-10 Transition States 142 4-11 Rates of Multistep Reactions 144 4-12 Temperature Dependence of Halogenation 145 4-13 Selectivity in Halogenation 146 4-14 The Hammond Postulate 151 Problem-Solving Strategy: Proposing Reaction Mechanisms 153 4-15 Radical Inhibitors 155 4-16 Reactive Intermediates 156 Summary: Reactive Intermediates 162 Chapter 4 Glossary 162 Study Problems 165 Contents vii
Contents STEREOCHEMISTRY 169 17元 5.3 (R) ature of Asymmetric Carbon Atoms 176 ation of Enantiomers 186 56 Racemic Mixtures 187 and Optical Purity 188 5-8 Chirality of Conformationally Mobile Systems 189 5-9 Chiral Compounds without Asymmetric Atoms 191 5-10 Fischer Projections 193 Summary:Fischer Projections and Their Use 198 5-11 Diastercomers 198 Summary:Types of Isomers 199 Stereochemistry of Molecules with Two or More Asymmetric Carbons 200 eso Comp 0 nfiguration 20 mers 5-16 Study Problems 211 ALKYL HALIDES:NUCLEOPHILIC SUBSTITUTION O AND ELIMINATION 215 Introduction 215 6-3 Halides 216 Halides 218 re of Alkvl Halides 220 6-5 Physical Pr s of alkyl Halides 221 aration of Alky]Halides 223 Summary:Methods for Preparing Alkyl Halides 226 6.7 Reactions of Alkyl Halides:Substitution and Elimination 228 6-8 Second-Order Nucleophilic Substitution:The S2 Reaction 229 Key Mechanism:The SN2 Reaction 230 69 Generality of the SN2 Reaction 23 Summary:Sy2 Reactions of Alkyl Halides 231 6-10 Factors Affecting Reactions:Strength of the Nucleophile 233 n Nucleophilic city 234 keactivity of the S SN2 R ions 237 em the on ey Me SNI Reaction 243 244 6.14 of the s 47 615 nts in S.1 Reactions249 6-16 Comparison of Sxl and Sx2 Reactions 252 6.17 First-Order Elimination:The El Reaction 25: Key Mechanism:The E1 Reaction 255 Summary:Carbocation Reactions 259
viii Contents 5 STEREOCHEMISTRY 169 5-1 Introduction 169 5-2 Chirality 170 5-3 (R) and (S) Nomenclature of Asymmetric Carbon Atoms 176 5-4 Optical Activity 181 5-5 Biological Discrimination of Enantiomers 186 5-6 Racemic Mixtures 187 5-7 Enantiomeric Excess and Optical Purity 188 5-8 Chirality of Conformationally Mobile Systems 189 5-9 Chiral Compounds without Asymmetric Atoms 191 5-10 Fischer Projections 193 Summary: Fischer Projections and Their Use 198 5-11 Diastereomers 198 Summary: Types oflsomers 199 5-12 Stereochemistry of Molecules with Two or More Asymmetric Carbons 200 5-13 Meso Compounds 201 5-14 Absolute and Relative Configuration 203 5-15 Physical Properties of Diastereomers 205 5-16 Resolution of Enantiomers 206 Chapter 5 Glossary 209 Study Problems 211 6 ALKYL HALIDES: NUCLEOPHILIC SUBSTITUTION AND ELIMINATION 215 6-1 Introduction 215 6-2 Nomenclature of Alkyl Halides 216 6-3 Common Uses of Alkyl Halides 218 6-4 Structure of Alkyl Halides 220 6-5 Physical Properties of Alkyl Halides 221 6-6 Preparation of Alkyl Halides 223 Summary: Methods for Preparing Alkyl Halides 226 6-7 Reactions of Alkyl Halides: Substitution and Elimination 228 6-8 Second-Order Nucleophilic Substitution: The SN2 Reaction 229 Key Mechanism: The SN2 Reaction 230 6-9 Generality of the SN2 Reaction 231 Summary: SN2 Reactions of Alkyl Halides 231 6-10 Factors Affecting SN2 Reactions: Strength of the Nucleophile 233 Summary: Trends in Nucleophilicity 234 6-11 Reactivity of the Substrate in SN2 Reactions 237 6-12 Stereochemistry of the SN2 Reaction 241 6-13 First-Order Nucleophilic Substitution: The SN 1 Reaction 243 Key Mechanism: The SN 1 Reaction 244 6-14 Stereochemistry of the SNI Reaction 247 6-15 Rearrangements in SNI Reactions 249 6-16 Comparison of SNI and SN2 Reactions 252 Summary: Nucleophilic Substitutions 254 6-17 First-Order Elimination: TheEl Reaction 255 Key Mechanism: The E1 Reaction 255 Summary: Carbocation Reactions 259