§07§§Nucleophilic aromatic substitutions (SNAr) belong to one of the most important reaction classes in organic chemistry. This reaction type is also of considerable practical use for transformations in medicinal and agricultural chemistry, as it facilitates access to complicated and functionalized molecules. §16§Providing an updated overview of SNAr substitutions, balancing both mechanistic and synthetic viewpoints, this book gives a comprehensive account of this versatile field. The first chapter deals with a mechanistic analysis of the factors governing the feasibility of SNAr substitutions, providing useful information to predict the regio- and stereoselectivity control of the reactions and to define the conditions for concerted SNAr processes. Reflecting the key role played by these species as intermediates in most SNAr reactions, Chapter 2 then discusses the chemistry of anionic s-complexes. Chapter 3 describes the new concept of superelectrophilicity which has emerged from the kinetic and thermodynamic data collected in the preceding chapters , while the numerous synthetic applications are considered in depth in the chapters that follow on intermolecular, intramolecular, and nucleophilic aromatic substitutions of hydrogen. The final chapter brings together concise yet comprehensive §16§discussions surrounding SNAr photosubstitutions, radical substitutions, and ANRORC substitutions. §Authored by an eminently respected chemist who has contributed greatly to the field over the past two decades, this is a valuable information source for all organic chemists working in academia or the pharmaceutical and agrochemical industries. §04§THE SNAr REACTIONS: MECHANISTIC ASPECTS§Introduction§Activation of the Aromatic System: Driving Force for SNAr Reactions§Leaving Group, Nucleophile, Solvent, and Medium Effects§Effects of Specific Structural Variations in the Activated Ring§Spectral Evidence for the Intermediacy of sigma-Complexes in SNAr Reactions§Base Catalysis in SNAr Reactions§Regioselectivity in SNAr Reactions§Asymmetric SNAr Substitutions§Concerted SNAr Substitutions§Conclusion§ §STRUCTURE AND REACTIVITY OF ANIONIC SIGMA-COMPLEXES§Introduction§Structural Features of sigma-Complexes§Thermodynamics and Kinetics of sigma-Complex Formation§ §THE SUPERELECTROPHILIC DIMENSION IN SNAr AND RELATED SIGMA-COMPLEXATION PROCESSES§Introduction§The Classical Domain of SNAr and Anionic sigma-Complexation Reactivity§Reaching the Superelectrophilic Dimension§The Synthetic Potential of sigma-Complexation and SNAr Reactivity in the Superelectrophilic Dimension§O §04§rigin of the Superelectrophilicity of Neutral 10pi Heteroaromatics§ §SYNTHETIC ASPECTS OF INTERMOLECULAR SNAr REACTIONS§Introduction§Intermolecular Displacements of a Nitro Group§Intermolecular Displacements of Halogen and Other Leaving Groups§Conclusion§ §INTRAMOLECULAR SNAr REACTIONS§Introduction§SNAr Cyclizations§Smiles Rearrangements§Conclusion§ §NUCLEOPHILIC AROMATIC SUBSTITUTIONS OF HYDROGEN§Introduction§Reactions Involving Oxidation of sigma-Complex-Type Intermediates§Vicarious Nucleophilic Aromatic Substitutions of Hydrogen (VNS)§Deoxygenative SNArH Substitutions§Cine and Tele Substitutions§Conclusion§ §OTHER SNAr SUBSTITUTION PATHWAYS§SN(ANRORC) Substitutions§Radical Nucleophilic Aromatic Substitutions§Nucleophilic Aromatic Photosubstitutions§
