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.