Direct CH perfluoroalkylation of (di)benzo(hetero)arenes in aqueous media

Perfluorobutylation of a series of benzo- and dibenzo-(hetero)aromatic compounds without formal leaving groups is achieved efficiently in organic solvent: water mixtures under photostimulation. The methodology is compared to previously reported trifluoromethylation strategies of these nuclei in terms of product yields and regioselectivity. The global reaction is a radical homolytic aromatic substitution process, where the perfluoroalkyl-substituted cyclohexadienyl radical intermediate is first oxidized and then a proton transfer sequence affords the products. This constitutes the first report for a direct perfluoroalkylation strategy of dibenzo(hetero)arenes without formal leaving groups.