Sandmeyer Difluoromethylation of (Hetero-)Arenediazonium Salts

A Sandmeyer-type difluoromethylation process has been developed that allows the straightforward conversion of (hetero-)­arenediazonium salts into the corresponding difluoromethyl (hetero-)­arenes under mild conditions. The actual difluoromethylating reagent, a difluoromethyl–copper complex, is formed in situ from copper thiocyanate and TMS–CF₂H. The diazonium salts are either preformed or generated in situ from broadly available aromatic amines