Silica-assisted Suzuki-Miyaura reactions of heteroaryl bromides in aqueous media

A new palladium catalysis system has been developed for the Suzuki-Miyaura cross-coupling reactions of heteroaryl bromides in aqueous media. The method allows the preparation of a variety of heterobiaryls in good to excellent yields under mild reaction conditions without the use of phosphine ligands. Silica gel is found to be crucial to the successful performance of the reactions and the catalytic system can be reused eighteen times with high efficiency.