Mn(OAc)3-Mediated Hydrotrifluoromethylation of Unactivated Alkenes Using CF3SO2Na as the Trifluoromethyl Source

A simple and efficient method for hydrotrifluoromethylation of unactivated alkenes was reported. The reaction relied on the single electron oxidation of a commercially available sodium trifluoromethanesulfinate (CF3SO2Na, Langlois' reagent) using Mn(OAc)3·2H2O as the oxidant and the subsequent addition of trifluoromethyl radical to C═C double bonds. The reaction proceeded readily under mild conditions with good tolerance of a variety of functional groups in the substrates. The preliminary reaction mechanism was studied with deuteration, radical clock, and TEMPO inhibition experiments.