organic and bio-organic mechanismsPDF电子书下载

1THE TRANSITION STATE 1

1.1 Mechanism as a progression of states 1

1.2 Structure and its interpretation 1

1.3 Interconversion of states—reaction and encountercomplexes 4

1.4 Methods of representing reaction mechanisms 4

1.5 General considerations concerning reaction mechanisms 6

1.6 Energy transfer, redistribution and relaxation 12

1.7 Stereoelectronic effects 16

1.8 Principle of non-perfect synchronization 18

1.9 Principle of least nuclear motion 19

1.10 Is the transition state a molecule? 19

2 KINETICS AND MECHANISM 23

2.1 Introduction 23

2.2 Kinetic method 24

2.3 Rate law and mechanism 25

2.4 Steady state and non-steady state 25

2.5 Rate-limiting step 26

2.6 Curtin-Hammett principle 28

2.7 Which transition state is being observed kinetically? 29

2.8 Demonstration of intermediates by kinetics 30

2.9 Change in mechanism 33

2.10 Rules for change in mechanism or rate-limiting step 36

2.11 Trapping of intermediates 37

2.12 Composition of the transition state of the rate-limiting step 38

2.13 Kinetic ambiguities 40

2.14 Microscopic reversibility 42

2.15 Kinetic and thermodynamic control 43

2.16 Isotope labelling techniques and detection of intermediates 45

3 THE EFFECT OF CHANGES IN REACTANT STRUCTURE 52

3.1 Introduction 52

3.2 Comparison of known with unknown—the Lefflerapproach 52

3.3 Polar and steric substituent effects 53

3.4 Hammett's equation 55

3.5 Bronsted's equation 62

3.6 Transition-state acidity and transition-state complexation 74

3.7 Topology of transition states 75

4 KINETIC AND EQUILIBRIUM ISOTOPE EFFECTS 80

4.1 Origin of isotope effects 80

4.2 Measurement of kinetic isotope effects 84

4.3 Primary isotope effects 86

4.4 Solvent isotope effects 88

4.5 Heavy-atom isotope effects 92

4.6 Secondary isotope effects and transition-state structure 94

5 TRANSITION STATES FROM EXTERNAL EFFECTS 97

5.1 Introduction 97

5.2 Solvent effects 97

5.3 Reactions in strongly acidic and strongly basic media 101

5.4 Solvent ionizing power 105

5.5 Variation of pressure and temperature 107

6 TRANSITION STATE STRUCTURES-ANOMALIES 116

6.1 Introduction 116

6.2 Reactivity-selectivity relationship 116

6.3 Microscopic medium effects 121

6.4 Curvature in free-energy relationships 123

6.5 Bronsted anomalies 128

6.6 Do experimental parameters directly measure transition-statestructures? 130

7 BIO-ORGANIC GROUP TRANSFER REACTIONS 134

7.1 Relative timing of bond formation and bond fission 134

7.2 Acyl group transfer 145

8 CATALYSIS 161

8.1 Reactivity 161

8.2 Coenzymes 166

8.3 Proton transfer 174

8.4 Metal ions 179

8.5 Intramolecular reactions 184

9 COMPLEXATION CATALYSIS 196

9.1 General considerations 196

9.2 Covalent catalysis 198

9.3 Inclusion complexation 199

9.4 Catalysis by organized aggregates and phases 205

9.5 Future directions 212

10 SOME ENZYMES 214

10.1 Introduction 214

10.2 Enzymes catalysing acyl group transfer 215

10.3 Catalysis of proton transfer reactions 224

10.4 Carbon-carbon bond formation and fission 232

10.5 Transfer of the hydride ion 235

10.6 Alkyl group transfer 240

APPENDICES 247

A.1 IUPAC system for symbolic representation of reactionmechanisms 247

A.2 Supplementary tables 248

A.3 Estimation of ionization constants 258

A.4 Estimation of partition coefficients 261

A.5 Fitting data to theoretical equations 264

REFERENCES 267

INDEX 291