An expedient approach to the difluoromethylation of imidazoles and
benzimidazoles has been developed. The key feature of the procedure
is the gradual generation of the difluoromethylation reagent in
the reaction mixture, which is achieved by the simultaneous addition
of chlorodifluoromethane and alkali. The method is applicable to
functionalized substrates and allows the corresponding 1-(difluoromethyl)imidazoles
and -benzimidazoles to be prepared in 60-95% yield
on a hundred-gram scale.
fluorine compounds - heterocycles - imidazoles - benzimidazoles - difluoromethylation