Mechanisms in Advanced Organic Chemistry

Preface......Page 6
Foreword\n......Page 8
Contents......Page 10
Nomenclature......Page 20
Structure and Stability......Page 21
1. Reaction with nucleophiles......Page 25
4. Addition to unsaturated systems......Page 26
Non-Classical Carbocations......Page 27
Generation of Non-Classical Carbocations......Page 28
Stability\n......Page 29
Abstraction of hydrogen by a base......Page 30
From Unsaturated Compounds......Page 31
Addition Reactions of Alkyl (Sp3) Anions......Page 32
Elimination Reactions of Carbanions......Page 33
Oxidation Reactions of Carbanions......Page 34
Intramolecular Additions......Page 36
Sigmatropic Carbanion Rearrangement......Page 37
What are Concerted Reactions?\n......Page 38
Stepwise Mechanism......Page 39
What are Stereoselective and Stereospecific Reactions?\n......Page 40
Theory of Concerted Reactions......Page 41
Ethylene System\n......Page 42
Butadiene System......Page 44
Frontier Orbital Approach......Page 45
Conjugated Triene......Page 46
Introduction......Page 47
Classification......Page 48
General Rule for Pericyclic Reactions......Page 49
What is Symmetry Allowed and Symmetry Forbidden Reaction?\n......Page 50
Woodward-Hoffmann Rule......Page 51
σ Bonds Involved in Cycloaddition Reactions......Page 54
Some More Examples of 2 + 2 Cycloadditions......Page 55
Photochemical Cycloadditions......Page 57
2 + 3 Cycloadditions (1, 3 dipolar cycloadditions)......Page 58
2, 1 Cycloaddition......Page 60
Scope of Diels Alder Reaction......Page 61
Stereochemistry and Endo and Exo Addition......Page 63
Orientation (Regioselectivity)......Page 67
Diene Reactivity......Page 68
Dienophile Reactivity......Page 69
Intramolecular Diels-Alder Reactions......Page 71
Introduction......Page 72
Thermal Electrocyclic Reactions......Page 74
2π System......Page 75
4π System......Page 76
6π System......Page 81
Electrocyclic Reactions of Radicals......Page 84
Metal-Catalysed Electrocyclic Reactions......Page 85
Photochemical Electrocyclic Reactions......Page 86
Introduction......Page 88
Hydrogen Migrations......Page 89
Formation of a Cyclic Transition State Structure......Page 91
Some other examples of Hydrogen Shifts\n......Page 93
Migrations in Cyclopropane Ring......Page 94
Selection Rules......Page 95
Shifts in Neutral Species......Page 97
Shifts in Charged Species......Page 98
Application of FMO Method......Page 99
Cope and Claisen Rearrangements......Page 100
The Cope Rearrangement\n......Page 102
The Oxy-Cope Rearrangement......Page 104
The claisen rearrangements\n......Page 105
Some Other Examples......Page 106
[2, 3] Sigmatropic Rearrangements......Page 108
The Ene Reaction......Page 109
Introduction......Page 111
Symmetry Allowed Cycloaddition of SO2 to a Diene......Page 112
Addition of Carbenes or Nitrenes......Page 113
Cheletropic Reactions Involving 6π Electrons......Page 114
2+2+2 Cycloadditions and Eliminations\n......Page 116
Cheletropic reactions Involving 8π Electrons......Page 117
General Introduction......Page 118
Compounds Having Double Bonds......Page 119
Relative Stabilities of Isomers......Page 121
Nomenclature of Geometrical Isomers\n......Page 122
Determination Of Configuration of Geometrical Isomers......Page 123
Some Physical Methods for the Determination of Configurations\n......Page 125
Stability and Inter Conversion of cis-trans Isomers......Page 128
Preparation of cis-trans Isomers......Page 129
Stereochemistry of Additions to Double Bonds......Page 131
Cis-Addition Reactions\n......Page 132
Trans-Addition Reactions\n......Page 135
Stereochemistry of Cyclic Compounds......Page 137
Importance of Stereochemistry......Page 138
Asymmetry and Chirality......Page 140
Diasteroisomers......Page 141
A Plane of Symmetry\n......Page 142
An Alternating Axis of Symmetry\n......Page 143
Nomenclature of Optical Isomers......Page 146
Fischer Projections......Page 153
Stereoisomerism in Cyclic Compounds......Page 154
Methods for Determining Absolute Configuration......Page 156
Asymmetric Synthesis (Asymmetric Induction)\n......Page 161
Asymmetric Transformation......Page 163
Mechanism of Asymmetric Syntheses......Page 164
Stereoselective and Stereospecific Reactions......Page 165
Resolution of Racemic Mixtures......Page 166
Racemisation......Page 169
Mechanism of Racemisation......Page 170
Walden Inversion (Optical inversion)\n......Page 171
Mechanism of Walden Inversion......Page 173
Conformation and Conformational Analysis\n......Page 175
Conformation of Ethane......Page 176
Conformation of Propane......Page 178
Staggered Forms\n......Page 179
Ring Strains in Cycloalkanes......Page 180
Principles of Conformation......Page 182
Rotation about Bonds involving Carbon Atoms in a State of sp2 Hybridisation......Page 183
Methods for Determining Conformation\n......Page 184
Conformational Asymmetry\n......Page 189
Conformations of Three to Five Membered Rings......Page 190
Stereochemistry of Cyclic Compounds......Page 192
Cyclopropane Rings......Page 193
Cyclobutane Rings......Page 195
Cyclopentane Rings......Page 196
Cyclohexane Rings......Page 197
Monosubstituted Cyclohexanes......Page 199
Disubstituted Cyclohexanes......Page 200
Disubstituted Cyclohexanes with Substituents in 1, 3 Positions\n......Page 201
Conformation and Chemical Reactivity......Page 202
Six-Membered Heterocyclic Rings......Page 204
Cyclooctane and Cyclononane......Page 205
Cyclodecane......Page 206
Baeyer’s Strain Theory......Page 207
Limitations of the Strain Theory......Page 209
Fused Ring System......Page 210
Expedited Organic Synthesis With Organosilicon Compounds\n......Page 212
Creation of a Bond......Page 213
Activation......Page 214
Some Applications of Organosilicon Compounds to Organic Synthesis......Page 215
Formation and Cleavage of Bonds to Silicon......Page 216
Organosilicon Protecting Groups......Page 218
Synthesis of Olefines......Page 219
Silylenes......Page 220
Silenes......Page 221
Silanones......Page 223
Silyl Anions......Page 224
Photolysis, Prolysis and Electron Transfer......Page 225
Some General Consideration\n......Page 228
Spectroscopy......Page 229
Lasers, Importance and Uses......Page 230
Ultraviolet and Visible Spectroscopy\n......Page 231
Origin of U.V. Absorption Spectra......Page 233
Colour in Organic Compounds......Page 234
Absorption in Organic Molecules......Page 235
Energy Levels in Different Molecular Orbitals......Page 236
Difference between n -> π* and π -> π* transition......Page 238
Applications of Ultraviolet Spectroscopy......Page 240
Introduction......Page 242
Origin of Infrared Spectra......Page 243
Molecular vibrations......Page 244
Types of Vibrations in Polyatomic Molecules......Page 245
Vibrations of Polyatomic Molecules......Page 246
Factors Influencing Vibrational Frequencies......Page 250
Instruments......Page 253
Source of Radiation......Page 254
Sampling techniques......Page 255
Finger Print Region......Page 256
Applications of Spectroscopy......Page 257
IR Spectra of Some Compounds......Page 258
Introduction......Page 259
Chemical Shifts and Number of Signals......Page 262
Instrumentation......Page 265
Expression of Chemical Shifts......Page 267
Factors Influencing Chemical Shift\n......Page 270
Solvents Used......Page 271
Origin of Multiplet Peaks......Page 273
Coupling Constants......Page 275
Interpretation of NMR spectra......Page 276
Applications of NMR Spectroscopy\n......Page 277
13C-NMR Spectroscopy (CMR)\n......Page 279
II Boron\n......Page 280
Applications of Mass Spectroscopy\n......Page 281
Principle of operation of mass spectrometer\n......Page 282
Interpretation of Some Spectra......Page 284
Mass Spectrum of Benzene, of 2,2,4 Trimethyl Pentane\n......Page 285
Some Guiding Principles for Finding the Base Peaks......Page 287
Use of a Spark Source\n......Page 288
Ozone......Page 292
Lead TETRA-ACETATE Pb(OAc)4\n......Page 293
Periodic Acid HIO4\n......Page 295
Osmium Tetroxide OSO4\n......Page 297
Selenium Dioxide SeO2\n......Page 298
Perbenzoic Acid......Page 299
Lithium Aluminium Hydride......Page 302
Sodium Borohydride......Page 305
Metal/Liquid Ammonia......Page 307
Some Metal Catalysts Used in Hydrogenation......Page 309
Raney Nickel Catalysts......Page 310
Platinum\n......Page 311
Palladium......Page 312
Alluminium Isopropoxide AI\n......Page 313
Diazomethane......Page 315
Liquid Ammonia......Page 317
N-Bromosuccinimide......Page 321
Trifluroacetic Acid......Page 324
Trifluoroacetic Anhydride......Page 325
Sodium Amide(Sodamide)......Page 326
Dimethyl Sulphoxide(DMSO)......Page 328
Boron Trifluoride......Page 330
Index......Page 332