CONTENTS
1. Introduction - Classification of specific Salt Effects = 1
1.1 Specific Salt Effects Involving th Salt's Lewis Acid or Base Character = 2
1.2 Salt Effects Arising from Exchange Reactions between Two Ion Pairs = 3
1.3 Salt Effects Connected with the Position of Ionic Dissociation Equilibria = 4
1.4 specific Salt Effects Affecting the Structure of the Activated Complex in the Transition State : Effect on the Stereo- and Regioselectivities = 5
1.5 Salt Effects Arising from Specific Associations with Protic Solvents (Drying Effect) = 6
References = 8
2. Effects of Salts on the Rates of single Bond Cleavage Reactions = 11
2.1 Specific Salt Effects concerning the Heterolytic Cleavage of C - Y Bonds = 11
2.1.1 Ionization of C - X Bonds = 11
2.1.1.1 Electrophilic assistance = 13
2.1.1.2 Nucleophilic assistance by salts - effects of anions = 16
2.1.2 Unimolcular Solvolysis Reactions (S$$_{N}$$l, E$$_{1}$$) = 16
2.1.2.1 Common ion mass effect = 18
2.1.2.2 "Normal" and "special" salt effects = 19
2.1.2.3 Retardation by the drying salt effect : S$$_{N}$$I reactions in mixed solvents = 22
2.2 Specific Salt Effects in Bimolecular Nucleophiles Reactions = 24
2.2.1 S$$_{N}$$2 Reactions Brought About by anionie Nucleophiles [Scheme (2-23)] = 24
2.2.1.1 Effect of the cation accompanying the anionic nucleophilie : ionic association or complexation of the electrophile = 25
2.2.1.2 Salt effects in S$$_{N}$$2 reactions involving hard anionic reactants = 26
2.2.1.3 Salt effects in S$$_{N}$$2 reactions involving soft anionic reactants = 28
2.2.2 S$$_{N}$$2 Reactions Involving Electrically Neutral Nucleophiles = 30
2.2.2.1 Effect according to the nature of the salt anion = 31
2.2.2.2 The case of alkali metal fluorides = 34
2.2.2.3 Use of tetraalkylammonium fluorides = 36
2.2.2.4 Use of fluorides on solid mineral supports = 37
2.2.3 Other Cases of Heterolytic C - X Bond Cleavage = 38
2.2.3.1 Aromatic nucleophilic substitutions (S$$_{N}$$Ar) = 38
2.2.3.2 Elimination reactions = 42
2.3 Nucleophilic Reactions with a Hydrogen Atom Reactive Site = 43
2.3.1 Cation Effects on C - H Bond Ionization caused by a Base B$$^{\ominus}$$ = 43
2.3.2 C - H Bond Ionization Caused by Alkali Metal Fluorides = 46
References = 47
3. Effects of Salts on Rates of Addition Reactions to Multiple Bonds = 55
3.1 Anionic Nucleophilic Addition (AdN) to ○ = O and Similar Bonds = 55
3.1.1 Effect of the Cation Introduced with the Anionic Reagent : Carbonyl Complexation or Ionic Association = 56
3.1.1.1 Carbonyl complexation : ○ = O ... M$$^{\oplus}$$ = 56
3.1.1.2 Ionic association Nu$$^{\ominus}$$ M$$^{\oplus}$$ = 57
3.1.1.3 Cation effects in AN C = O reactions = 59
3.1.2 Types of Salt Effects in A N C = O Reactions = 59
3.1.2.1 Effects due to added salt cations : carbonyl complexation or association with the reactant = 59
3.1.2.2 Drying effects in protic media = 60
3.1.3 Salt Effects in Alkaline Ester Hydrolysis = 61
3.1.3.1 Aliphatic esters = 61
3.1.3.2 Aromatic esters = 62
3.1.3.3 The case of phenyl acetate = 63
3.1.3.4 Explanation in terms of frontier orbitals = 64
3.1.4 Examples of Salt Effects in A N C = O reactions = 66
3.1.4.1 Positive salt effects = 66
3.1.4.2 Negative salt effects = 67
3.1.4.3 Catalysis by triyl perchlorate = 68
3.1.5 A N C = O Reactions Caused by Electrically Neutral Reagents = 68
3.1.6 Case of Other Unsaturated Compounds Having Electrophilic Character : Nucleophilic Addition to Nitriles = 70
3.2 Double Activation : Bifunctional Catalysis = 72
3.2.1 The Salt Taking Part as one of the Components in Double Activation = 73
3.2.1.1 As an electrophilic catalyst by mcans of M$$^{\oplus}$$ = 73
3.2.1.2 As nucleophilic catalyst by menas of X$$^{\ominus}$$ = 76
3.2.2 The Salt Taking Part as a Bifunctional Catalyst = 77
3.3 Addition Reactions to C = C Double Bonds = 79
3.3.1 General Points : Substituent Effects and Types of Addition = 79
3.3.1.1 Donor substituent effects = 80
3.3.1.2 Withdrawing substituent effects = 80
3.3.1.3 Particular case of C = C double bond α to C = O = 80
3.3.2 Electrophilic Addition (AdE) = 81
3.3.2.1 Acceleration resulting from the cation effect = 82
3.3.2.2 Acceleration brought about by the anion = 85
3.3.2.3 Acceleration of olefin oxidation by thallic salts in aqueous media through salt drying effects = 88
3.3.3 Aromatic Electrophilic Substituion = 88
3.3.3.1 Anisole acylation = 88
3.3.3.2 Mercuration of benzene : salt drying effects = 89
3.3.4 Nucleophilic Addition to Double Bonds α to C = O = 90
3.3.4.1 Accelerating effects due to cation = 90
3.3.4.2 Inhibiting effects due to the cation = 92
3.3.4.3 Salt effects = 94
3.3.5 Particular Case of Halogen Addition to C＝C＝C＝O Conjugated Systems References = 95
4. Effects of Salts on Reaction Orientation (Regioselectivity) = 103
4.1 Reactant Organization in the Vicinity of the Cation = 103
4.1.1 Macrocycle Synthesis : the "Template Effect" = 103
4.1.1.1 Synthesis of macrocycles in basic media = 103
4.1.1.2 Acid catalyzed macrocycle synthesis = 106
4.1.2 Effects of Sales on Intramolecular Cyclizations = 107
4.1.2.1 "Intramolecular self-solvation" effect = 107
4.1.2.2 Synthesis of benzo-18-crown-6 = 107
4.1.3 Effect of Salts on Metallation Regioselectivity = 109
4.2 Effects of Salts on Regioselectivity of Anionic Reactions = 110
4.2.1 Effects involving Electrophilic Reactants = 110
4.2.1.1 Epoxide ring opening = 110
4.2.1.2 β-elimination reactions = 115
4.2.1.3 Reactions involving carbonyl compounds = 121
4.2.2 Effects Arising from the Nucleophilic Reagent (Case of Mesomeric Anions) = 127
4.2.2.1 Effect of salts on the O／C ratio in an aprotic solvent = 128
4.2.2.2 Effect of salts on the O／C ratio in protic solvents = 130
4.2.2.3 Effect of salts on the O／C ratio in the case of aryloxy anions = 131
4.2.2.4 Effect of salts on the regioselectivity of alkylation of oximates (○＝N－O$$^{\ominus}$$ M$$^{\oplus}$$ ) = 134
4.2.2.5 Effects of salts on the ambident reactivity of aminoacids (O／N alkylation ratio) = 135
4.3 Effects of Salts on the Nature and Distribution of AdN2 Reaction Products = 136
5. Effects of Salts on Reaction Stereochemistry = 145
5.1 Effects Concerning the Electrophilic Reactant = 145
5.1.1 Bimolecular Nucleophilic Substitutions = 145
5.1.1.1 Effects at carbon = 145
5.1.1.2 Effects at silicon = 145
5.1.1.3 Effects at germanium = 147
5.1.1.4 Effects at phosphorus = 148
5.1.2 Ring-opening of Epoxides = 149
5.1.3 β-Elimination (Syn vs. Anti Elimination) = 150
5.1.4 Reactions of Addition to Carbonyl Compounds = 151
5.1.4.1 Stereochemistry of additions to cyclic ketones = 151
5.1.4.2 Stereochemistry of aldol condensations = 157
5.1.4.3 Stereochemistry of the Wittig-reaction = 159
5.1.4.4 Salt effects in asymmetric synthesis = 156
5.1.5 Nucleophilic Addition to Couble binds conjugated with Electron With drawing Groups = 169
5.1.5.1 Stereochemistry of Michael-type reactions = 169
5.1.5.2 Michael-type asymmetric synthesis = 172
5.1.5.3 Salt effects in asymmetric Michael reactions = 175
5.1.6 Salt Effects in the Steric course of Nucleophilic Additions of Halogens = 178
5.2 Effects on the Anionic Nucleophilic Reactant = 180
5.2.1 C-Alkylation of Carbanionic Species = 180
5.2.1.1 Influence of association between the carbanion and its M$$^{\oplus}$$ counterion = 181
5.2.1.2 Role of the cation in the alkylation of carbanionic species α to a sulfoxide group : salt effects = 184
5.2.1.3 Role of the cation in asymmetric alkylations = 186
5.2.1.4 α-Alkylation of ketones = 186
5.2.2 O-alkylation of Enolates of β-Dicarbonyl compounds = 190
5.3 Electrophilic Additions : effects of Salts on Sterochemistry = 192
5.4 Salt Effects on the Steric Course of the Favorskii Rearrangement = 195
5.4.1 Case of α-Haloketones Without a Mobile α' Hydrogen = 196
5.4.2 Case of α-Haloketones with a Mobile α' Hydrogen = 196
5.5 Medium Effects on the Stereochemistry of Enolate Ketonization (Protonation) = 200
5.5.1 Dissociating Protic Medium : Effect of pH = 200
5.5.2 Cation Effects on Ketonization Stereochemistry in Inert Solvents = 202
References = 203
6. Specific Effects of Salts on Equilibria = 211
6.1 Concepts of Activity and Activity Coefficients Their Significance in Equilibria = 211
6.2 Specific Effects of Salts on Equilibria Preceding the Slow Step of Various Reactions = 213
6.3 Some Examples illustrating the Effects of Salts on Uncatalyzed Pre Equilibrated Reactions = 216
6.4 Salt Effects resulting from Equilibria between Ion Pairs = 219
6.4.1 Reactions between Neutral Molecules to Give two Oppositely Charged Ions = 220
6.4.1.1 Acid-Base equilibria between neutral species = 220
6.4.1.2 Equilibria for the acylation of neutral molecules = 222
6.4.2 Effects of Salts on Product Distribution for Reactions Taking Place Within Ion Pairs = 225
6.4.2.1 Reactions of "activated sulfoxides", S$$^{\oplus}$$－O－CO－R, X$$^{\ominus}$$ = 225
6.4.2.2 Epoxide ring opening in acid media = 228
6.4.2.3 Elctrophilic additions to alkenes = 229
6.4.2.4 Aromatic electrophilic substitutions = 230
6.4.2.5 Reductions by silanes in acid media = 230
6.4.2.6 Reactions Involving Radical Ions = 231
6.4.3 Reactions Involving Radical Ions = 232
6.4.3.1 Photoisomerizations = 233
6.4.3.2 Photochemical organic reactions = 234
6.4.3.3 Reactivity of aromatic radical cations = 237
7. Salt Effects in Organometallic Chemistry = 241
7.1 Main Group Metals : Li, Mg = 241
7.1.1 Salt Effects in Organolithium Chemistry = 241
7.1.1.1 Salt effects involving the organolithium reagent = 241
7.1.1.2 Salt Effects onvolving the substrate = 244
7.1.1.3 Stabilization of α-halo organolithium reagents by lithium salts : 〉／c(X) Li (carbenodis) = 245
7.1.1.4 Case of organolithium reagents of the type R(Li)C＝O = 247
7.1.1.5 Structure and reactivity of lithium amides = 249
7.1.2 Salt Effects in Grignard Reagent Chemistry = 250
7.1.2.1 Structure of Grignard reagents = 250
7.1.2.2 Salt effects = 252
7.2 Salt Effects in Transition Metal Chemistry = 254
7.2.1 Anion Effects = 254
7.2.1.1 Anion effects on the structure of complexes = 254
7.2.1.2 Effect of X$$^{\ominus}$$ anions on nucleophilicity of camplexes = 255
7.2.1.3 Enhancement by anions of the reducing power of zerovalent metal complexes = 266
7.2.1.4 Anion efects on the stereo and regioselectivity of reactions catalyzed by palladium complexes = 269
7.2.2 Cation Effects = 272
7.2.2.1 Cation participation in migratory insertions = 273
7.2.2.2 Cation Effects on the st겨cture of anionic complexes = 274
7.2.2.3 Cation effects on the reactivity of anionic complexes = 275
7.2.3 Reactions Taking Place Within a contact Ion Pair = 279
References = 279
8. Appendix = 289
8.1 Revision of Some General Concepts = 289
8.1.1 Ionic Strength of a Solution = 289
8.1.2 Acidity Functions = 289
8.2 Solvent Classification = 291
8.2.1 Protic and Aprotic solvents = 291
8.2.2 Donor and Aceptor solvents = 291
8.2.2.1 Donor solvents ; donor number scale = 291
8.2.2.2 Aceptor solvents ; aceptor number scale = 292
8.3 Ionic associations = 292
8.3.1 Coulombic Interactions = 292
8.3.2 "Hard" and "Soft" Ions (HSAB Classification : Hard and Soft Acids and Bases) = 293
8.3.3 Preferential Ionic Associations : "Symbiotic Effect" = 294
8.3.4 The Various Types of Ion Pair = 294
8.3.5 Concept of Aggregates = 295
8.4 Perturbation Theory applied to Chemical Reactivity = 295
8.4.1 Klopman Equation : Charge and Orbital control = 295
8.4.2 Applications to Reactivity = 296
8.4.2.1 Reaction kinetics = 296
8.4.2.2 Reaction regioselectivity = 297
8.4.3 Application to the HSAB Principle : Interactions Between Soft Ions (Symbiotic Effect) = 297
8.5 Concerning Transition Metal Chemistry = 298
8.5.1 Degree of Coordination Unsaturation of a Transition Metal in a complex = 298
8.5.2 Formal Oxidation State of a Transition Metal in a Complex = 299
8.5.3 Oxidative Addition and Reductive Elimination = 299
8.5.4 Intramolecular Insertions = 300
8.6 Hydrophobic and Hydrophilic Effects : Salting-In and Salting-Out Effects = 301
References = 302
9. Supplement - Recent Publications = 305
Index = 311
