Developing Bis(imino)acenaphthene-Supported N-Heterocyclic Carbene Palladium Precatalysts for Direct Arylation of Azoles

On the basis of the strategy of developing highly efficient protocol for Pd-catalyzed cross-coupling reactions, a series of bulky bis(imino)acenaphthene (BIAN)-supported Pd-PEPPSI complexes were synthesized, characterized, and applied in direct arylation of azoles. The effect of backbone and N-moieties on NHCs was evaluated, and the reaction conditions were optimized. It was found that the bulky Pd-PEPPSI complexes could be successfully employed in cross-coupling of (hetero)aryl bromides with azoles at a low palladium loading of 0.5–0.05 mol % under aerobic conditions, demonstrating the ease of manipulation without glovebox and handling of solvents.