A simple and efficient protocol for a palladium-catalyzed ligand-free Suzuki reaction at room temperature in aqueous DMF

A convenient, effective and mild protocol has been developed for the palladium-catalyzed ligand-free Suzuki reaction of aryl bromides with arylboronic acids in aqueous N,N-dimethylformamide (DMF) in the presence of K2CO3 and a catalytic amount of PdCl2 in air at room temperature. It is noteworthy that the volume ratio of water-DMF and base play important roles in the reaction, and various functional groups are tolerated under the optimized conditions. Furthermore, this protocol could be extended to the cross-couplings of nitrogen-based heteroaryl halides with arylboronic acids in moderate to excellent yields.