Copper-catalyzed Ligand-Free Suzuki–Miyaura Coupling Reaction of Aryl Halides with Arylboronic Acid

A highly efficient and ligand-free approach for the Suzuki–Miyaura cross-coupling reaction of aryl halides with arylboronic acid catalyzed by CuI/Cs2CO3 in DMF has been developed. Under the described conditions, a category of aryl halides including iodides and bromides, whether electron-rich or electron-deficient, were coupled with arylboronic acid to give the target products (moderate to excellent yields). This catalytic system was less efficient in the reactions of aryl bromides as a higher reaction temperature was required to improve the yield.