Regiocontrolled palladium-catalyzed direct C2-arylation of a difluorobenzo[d]imidazole

Abstract

Conditions for the regioselective palladium-catalyzed direct arylation of a 6,7-difluorobenzo[d]imidazole using aryl bromides as the coupling partners are described. The site selectivity of the arylation was found to be in favor of the C2-carbon of the difluorobenzo[d]imidazole; whereas the difluoro-substituted ring remained untouched, even in the presence of an excess of aryl bromide. This method tolerates a variety of substituents at para-, meta- and ortho-positions on the aryl bromide and also N-containing heteroaryl bromides.