Chelation-Assisted Regioselective Catalytic Functionalization of C–H, C–O, C–N and C–F Bonds

Transition-metal-catalyzed functionalization of unreactive carbon bonds such as C–H, C–O, C–N, and C–F bonds has been extensively studied over the last two decades. In this account we describe our studies on chelation-assisted catalytic transformations of unreactive carbon bonds in aromatic and olefinic compounds. Various C–C bond forming reactions are achieved by catalytic addition of C–H bonds to alkenes and alkynes, and via coupling reactions such as those of C–H, C–O, C–N, and C–F bonds with boronic esters. Methods for the conversion of C–H bonds into C–Si and C–X (X = halogen) bonds are also developed. The C–C bond forming reactions are applied to short syntheses of polycyclic aromatic hydrocarbons. 1 Introduction 2 Conversion of C–H Bonds into C–C Bonds 2.1 C–H Alkylation 2.1.1 Scope and Limitations 2.1.2 Mechanistic Studies 2.2 C–H Arylation 2.3 C–H Alkenylation 2.4 Introduction of Carbonyl Functionality via C–H Bond Cleavage 3 Conversion of Aromatic C–O, C–N and C–F Bonds into C–C Bonds by Coupling with Organoboronates 3.1 Coupling with Organoboronates via Aromatic C–O Bond Cleavage 3.2 Coupling with Organoboronates via Aromatic C–N Bond Cleavage 3.3 Coupling with Organoboronates via Aromatic C–F Bond Cleavage 4 Introduction of Heteroatoms at C–H Bonds 4.1 Silylation of C–H Bonds 4.1.1 Silylation of Aromatic C–H Bonds with Hydrosilanes 4.1.2 Silylation of Benzylic C(sp 3 )–H Bonds with Hydrosilanes 4.1.3 C–H Silylation with Vinylsilanes 4.2 Aromatic C–H Halogenation by Palladium-Catalyzed C–H Bond Cleavage and Electrochemical Oxidation 4.2.1 C–H Chlorination and Bromination 4.2.2 C–H Iodination and One-Pot C–H Iodination/Suzuki–Miyaura Coupling by ON/OFF Switching of Electric Current 5 Applications of C–H Functionalization in Short Syntheses of Polycyclic Aromatic Hydrocarbons (PAHs) 5.1 Convenient Synthesis of Multiarylanthracenes 5.2 Short Synthesis of Alkyl-Substituted Anthracenes and Pentacenes 5.3 Short Synthesis of Dibenzo[ a , h ]anthracenes and Picenes 6 Conclusions