Tunable base-controlled chemoselective synthesis of trifluoromethyl-containing -substituted benzimidazole-2-thiones and monofluorinated 4-benzo[4,5]imidazo[2,1-][1,3]thiazine.

A highly efficient base-controlled synthesis of -β-trifluoromethyl-substituted 2-benzo[]imidazole-2-thiones and 2-fluoro-4-benzo[4,5]imidazo[2,1-][1,3]thiazines hydroamination or defluorinative cyclizations of α-(trifluoromethyl)styrenes with 2-mercaptobenzimidazole was developed.