Copper-Promoted Trifluoromethanesulfonylation and Trifluoromethylation of Arenediazonium Tetrafluoroborates with NaSO2CF3

A tunable chemoselective trifluoromethanesulfonylation and trifluoromethylation of arenediazonium tetrafluoroborates with Langlois' reagent (NaSO2CF3) was developed. The Cu2O-catalyzed reaction in DMSO gave aryl trifluoromethanesulfones as the major products. On the other hand, the trifluoromethylated arenes were produced in the presence of oxidant tert-butyl hydroperoxide, CuBF4(MeCN)(4), and 2,2';6',2 ''-terpyridine (tpy). Both of these transformations proceed under mild conditions and tolerate functional groups.