The regioselective trifluoromethylation of 1,3-bis(vinyl triflates) in the absence of external trifluoromethyl sources

We report the regioselective trifluoromethylation of 1,3-bis(vinyl triflates) via an allyl radical intermediate. In this reaction, the trifluoromethyl radical exclusively attacks the 4-position of the 1,3-diketone derivatives. The observed regioselectivity can be rationalized on the basis of DFT calculations, which suggest that the attack at the 4-position is more favorable than that at the 2-position. We have also developed a one-pot procedure for the regioselective trifluoromethylation of 1,3-diketones.