Quantum Chemistry of Organic Compounds: Mechanisms of Reactions

1 Potential Energy Surfaces of Chemical Reactions. - 1.1 Introduction. Mechanism of Chemical Reaction and Quantum Chemistry. - 1.2 Choice of a Coordinate System and the Representation of a PES. - 1.3 Topography of the PES and Properties of a Reacting System. - 1.3.1 Critical Points. - 1.3.2 The Regions of the Minima on the PES. - 1.3.2.1 Vibrational Spectrum of Molecules. - 1.3.2.2 Calculation of Thermodynamic Functions of Molecules. - 1.3.2.3 Topological Definition of Molecular Structure. - 1.3.2.4 Structural Diagrams. - 1.3.3 Saddle Points on the PES. Transition States. - 1.3.3.1 Localization of the Transition States on the PES. - 1.3.3.2 Symmetry Selection Rules for Transition State Structures. - 1.3.3.3 Calculation of Activation Parameters of Reactions and of Kinetic Isotopic Effects. - 1.3.4 Pathway of a Chemical Reaction. - 1.3.4.1 Ambiguity of the Definition. - 1.3.4.2 A More Accurate Definition of the MERP and the Reaction Coordinate. - 1.3.4.3 Symmetry Demands on the Reaction Path. - 1.3.4.4 Chiral and Achiral Pathways of Degenerate Reactions. - 1.3.5 Empirical Correlations of the Reaction Pathways. - 1.3.5.1 Molecular Vibrations and the Reaction Coordinate. - 1.3.5.2 The Principle of Least-Motion. - 1.3.5.3 Structural Correlations of the Pathways of Chemical Reactions. - 1.4 Dynamic Approach. - 1.5 Tunnelling Effects in Chemical Reactions. - 1.6 Description of Nonadiabatic Reactions. - References. - 2 Quantum Chemical Methods for Calculating Potential Energy Surfaces. - 2.1 General Requirements upon the Methods for Calculating Potential Energy Surfaces. - 2.2 Nonempirical (ab initio) Methods. The Hartree-Fock Method. - 2.2.1 Closed Electron Shells. - 2.2.2 Open Electron Shells. - 2.2.3 Basis Sets of Atomic Orbitals. - 2.2.4 Electron Correlation. - 2.2. 5 The Problem of Stability of Hartree-Fock Solutions. - 2.3 Semiempirical Methods. - 2.3.1 The Extended Huckel Method. - 2.3.2 Semiempirical Selfconsistent Field Methods. - 2.3.2.1 The CNDO/2 Method. - 2.3.2.2 The MINDO/3 Method. - 2.3.2.3 The MNDO Method. - 2.3.2.4 The AM1 Method. - References. - 3 Effects of the Medium. - 3.1 A General Scheme for Calculating the Solvation Effects. - 3.2 Macroscopic Approximation. - 3.2.1 General Theory. - 3.2.2 Model Hamiltonians in the Macroscopic Approximation. - 3.2.2.1 Model Hamiltonian in the Kirkwood Approximation. - 3.2.2.2 A Model Hamiltonian Based on the Born Formula. Scheme of Solvatons. - 3.2.2.3 The Scheme of Virtual Charges. - 3.2.2.4 The Theory of Selfconsistent Reactive Field. - 3.3 Discrete Representation of Solvent Molecules. Model Hamiltonians in the Microscopic Approximation. - 3.4 Specific Features of the Supermolecular Approach in Studies of Solvation Effects. - 3.5 Statistical Methods for Studying Solutions. - References. - 4 Orbital Interactions and the Pathway of a Chemical Reaction. - 4.1 The Role of Frontier Orbitals. - 4.2 Theory of Orbital Interactions. - 4.3 Components of the Interaction Energy of a Reacting System in a Transition State. - 4.4 Isolobal Analogy. - References. - 5 Substitution Reaction. - 5.1 Nucleophilic Substitution at a Tetrahedral Carbon Atom. - 5.1.1 The SN2 Reactions. - 5.1.1.1 Stereochemistry of the Reactions. - 5.1.1.2 Reaction Coordinate and the Structure of the Transition State. - 5.1.1.3 Energetics and Stoichiometric Mechanism of the Gas-Phase SN2 Reactions. - 5.1.1.4 Effect of the Solvent. - 5.1.1.5 Reactions with Retention of Configuration of the Carbon Atom. - 5.1.2 The SN1 Reactions. - 5.2 Electrophilic Substitution at the Tetrahedral Carbon Atom. - 5.3 Nucleophilic Substitution at the Carbon Atom of the Carbonyl Group. - 5.3.1 The Stoichiometric Mechanism. - 5.3.2 Homogeneous Catalysis. - 5.3.3 Stereochemistry of the Reaction. - 5.3.3.1 The Direction of Nucleophilic Attack and Orbital Steering. - 5.3.3.2 Stereochemical Control of the Breakdown of the Tetrahedral Adduct. - 5.4 Aromatic Electrophilic Substitution Reactions. - 5.5 Nucleophilic Substitution at the Nitrogen, Phosphorus, and Sulfur Centers. - 5.5.1 Substitution at the Nitrogen Atom of Nitroso- and Nitro-Groups. - 5.5.2 Substitution at the Dicoordinate Sulfur Atom. - 5.5.3 Substitution at Tricoordinate Sulfur and Phosphorus Centers. - 5.5.4 Substitution at Tetracoordinate Phosphorus. - 5.5.5 Substitution at Pentacoordinate Phosphorus. - 5.5. 6 Inclusion of the Polytopal Rearrangements of Intermediates in the Overall Reaction Scheme. - References. - 6 Addition Reactions. - 6.1 Electrophilic Additions to Multiple Bonds. - 6.2 Nucleophilic Addition to Alkenes. - 6.3 Nucleophilic Addition to a Triple Bond. - References. - 7 Low-Energy Barrier Reactions. Structural Modelling. - 7.1 The Principle of Correspondence Between Structures of the Initial and the Transition State of Reaction. - 7.2 Nucleophilic Rearrangements and Tautomerizations. - 7.3 Cyclization Reactions. - 7.4 Topochemical Reactions. - References. - 8 Radical Reactions. - 8.1 Specific Features of the Theoretical Analysis of Radical Reactions. - 8.2 Free-Radical Reactions. - 8.2.1 Bond-Cleavage and Addition Reactions. - 8.2.2 Radical Substitution Reactions at the Tetrahedral Carbon Atom. - 8.3 Reactions with Formation of Biradicals. - 8.4 The Reactions of Carbenes. - 8.4.1 Addition to the Double Carbon-Carbon Bond. - 8.4.2 Insertion into ? -Bonds. - References. - 9 Electron and Proton Transfer Reactions. - 9.1 Electron Transfer Reactions. - 9.1.1 Single Electron Transfer Reactions in Organic Chemistry. - 9.1.2 Elementary Act of Electron Transfer. - 9.1.3 Theoretical Studies of the Mechanism of SRN1 Reactions. - 9.2 Proton Transfer Reactions. - 9.2.1 Potential Energy Curves and Activation Barriers. - 9.2.2 Stereochemistry. - 9.2.3 Proton Transfer in Systems with the Intramolecular Hydrogen Bonding. - 9.2.4 The Tunnelling Mechanism in Proton Transfer Reactions. - 9.2. 5 Double Proton Migrations. - References. - 10 Pericyclic Reactions. - 10.1 Reactions of Cycloaddition. - 10.1.1 [2 + 2]-Cycloaddition. - 10.1.2 [4 + 2]-Cycloaddition. - 10.2 Electrocyclic Reactions. - 10.3 Sigmatropic Rearrangements. - 10.4 Haptotropic Rearrangements. - 10.5 Ion-Radical Pericyclic Reactions. - References. - List of Abbreviations.