Developments in catalytic aromatic C-H transformations: Promising tools for organic synthesis

Catalytic carbon-carbon bond formation using transition metal complexes typically incorporates the use of an aryl halide or triflate compound (electrophile) in combination with an organometallic reagent (nucleophile). Versatile synthetic methods that allow C-C bond formation of aromatic compounds that proceed through transformation of C-H bonds would be of substantial value. Potential routes for C-C bond formation with aromatic substrates include the hydroarylation of unsaturated compounds (e.g., olefins or alkynes) and oxidative coupling of aromatic compounds and olefins or alkynes. Such reactions can proceed through metal-mediated transformation of C-H bonds. The range of reported catalysts and catalytic cycles for these classes of reactions have been reviewed herein.