Palladium-Catalyzed C-H Functionalization of Aryl Acetamides and Benzoquinones: Synthesis of Substituted Aryl Quinones.

An efficient synthesis of aryl-substituted quinones via Pd(II)-catalyzed C-H functionalization of less expensive and abundant benzoquinones with aryl acetamides is demonstrated. An auxiliary ligand ,-bidentate-directing group 8-aminoquinoline plays a crucial role in the success of the reaction. A broad range of substituted phenyl acetamides including commercially available drug molecules were examined and also found to be highly compatible with quinones. The aryl-substituted quinones were also easily converted into aryl-substituted hydroquinone derivatives. A plausible reaction mechanism was proposed to account for the selective distal C-H bond functionalization.