vi Contents 3.2.4 Cycloh xane 3.3 Con nfigurational isomers 33. Alkenes 3.32 Isomers with chiral centres Worked example 1537378415 Problems 4 Reactivity and mechanism A1 s:ions 42.1 4.3 and carbon radicals 431 Order A 4.6 al 4.62 s(involving ionic intermediates) 4.63 reaction: 4.7 electivity 4.9 thermodynamics and kinetics 4.9 hermodynamics 9912345566899060666 Kinetic versus thermodynamic control 4.100r ital overlap and energy 4.11 Guidelines for drawing reaction mechanisms Worked example Problems 5 Halog oalkanes 73 51 ucture 52.2 logenation of alka ogena 5.2.3 53 substitution 5.32 Nucleophilic 533 titution versus elimination 34437888992 Worked example Problems 6 Alkenes and alkynes 61 5 6.2 97 3.2.4 Cyclohexane 35 3.3 Configurational isomers 37 3.3.1 Alkenes 37 3.3.2 Isomers with chiral centres 38 Worked example 44 Problems 45 4 Reactivity and mechanism 49 4.1 Reactive intermediates: ions versus radicals 49 4.2 Nucleophiles and electrophiles 51 4.2.1 Relative strength 52 4.3 Carbocations, carbanions and carbon radicals 53 4.3.1 Order of stability 54 4.4 Steric effects 55 4.5 Oxidation levels 55 4.6 General types of reaction 56 4.6.1 Polar reactions (involving ionic intermediates) 56 4.6.2 Radical reactions 58 4.6.3 Pericyclic reactions 59 4.7 Ions versus radicals 59 4.8 Reaction selectivity 60 4.9 Reaction thermodynamics and kinetics 60 4.9.1 Thermodynamics 60 4.9.2 Kinetics 62 4.9.3 Kinetic versus thermodynamic control 65 4.10 Orbital overlap and energy 65 4.11 Guidelines for drawing reaction mechanisms 67 Worked example 68 Problems 69 5 Halogenoalkanes 73 5.1 Structure 73 5.2 Preparation 74 5.2.1 Halogenation of alkanes 74 5.2.2 Halogenation of alcohols 75 5.2.3 Halogenation of alkenes 77 5.3 Reactions 78 5.3.1 Nucleophilic substitution 78 5.3.2 Elimination 84 5.3.3 Substitution versus elimination 89 Worked example 91 Problems 92 6 Alkenes and alkynes 95 6.1 Structure 95 6.2 Alkenes 97 vi Contents