Pd-Catalyzed α-Arylation of α,α-Difluoroketones with Aryl Bromides and Chlorides. A Route to Difluoromethylarenes

We report the Pd-catalyzed alpha-arylation of alpha,alpha-difluoroketones with aryl and heteroaryl bromides and chlorides catalyzed by an air- and moisture-stable palladacyclic complex containing P(t-Bu)Cy-2 as ligand. The combination of this Pd-catalyzed arylation and base-induced cleavage of the acyl aryl-C-C bond within the alpha-aryl-alpha,alpha-difluoroketone constitutes a one-pot, two-step procedure to synthesize difluoromethylarenes from aryl halides. A broad range of electronically varied aryl and heteroaryl bromides and chlorides underwent these two transformations, providing alpha-aryl-alpha,alpha-difluoroketones, difluoromethylarenes, and difluoromethylheteroarenes in high yields.