Cross-coupling reactions catalyzed by an N-heterocyclic carbene-Pd(II) complex under aerobic and CuI-free conditions

A Pd-complex, (Cat. 3), has been successfully employed as a highly efficient and recyclable catalyst for the Sonogashira and Heck reactions of aryl bromides with various terminal acetylenes and olefins. The catalytic reactions proceed with excellent yields with a low catalyst loading (1.0 mol%) under aerobic and CuI-free conditions. A plausible mechanism has also been proposed for the reaction.