Chemoselective Chan–Lam Coupling Reactions between Benzimidazoline-2-thiones and Arylboronic Acids

An efficient Chan–Lam-type methodology for the selective synthesis of S-arylbenzimidazoles and N,S-diarylbenzimidazoles was developed. The selectivity was controlled by varying the amount of the catalyst Cu­(OAc)2·H2O, temperature, and solvent switching. These transformations feature a simple protocol, broad functional group tolerance, high selectivity, and good to excellent yields. It is noteworthy that these reactions represent the first examples of the application of the selective Chan–Lam coupling.