Silver-Mediated anti-Markovnikov and Markovnikov-Selective Hydrotrifluoromethylthiolation of Terminal Alkynes.

The first example of direct hydrotrifluoromethylthiolation of terminal alkynes in the presence of AgSCF3 and K2S2O8 was established for the synthesis of a variety of vinyl trifluoromethyl thioethers. The anti-Markovnikov and Markovnikov adducts were obtained in moderate to good yields via two different reaction systems. Studies to probe the mechanism of the anti-Markovnikov addition reactions including the radical trapping experiments, kinetic isotope effect experiments, and deuterated experiments for determination of H-sources were conducted.