Bioinspired photocatalysed C-H fluoroalkylation of arenes in water promoted by native vitamin B12 and Rose Bengal

The first perfluoroalkylation reaction of activated arenes (amino-substituted arenes and alkoxyarenes) has been achieved in water by employing the dyad Rose Bengal and hydrosoluble unmodified vitamin B12 (cyanocobalamin) as photocatalyst and co-catalyst, respectively. The reaction is performed under green LEDs irradiation and employs perfluoroalkyl bromides as perfluoroalkyl radical sources. In particular, the presence of vitamin B12 co-catalyst is found to be fundamental to elicit the formation of perfluoroalkyl radicals.