Synthetic Uses of Thio- and Selenoesters of Trifluoromethylated Acids. 1. Preparation of Trifluoromethyl Sulfides and Selenides

Trifluorothioacetates (CF3CO−S−R, from (CF3CO)2O and thiols) as well as trifluoromethanethio- or trifluoromethaneselenosulfonates (CF3SO2−Y−R; Y = S, Se; from CF3SO2Na, RYYR, and Br2) can be formally decarbonylated or desulfonylated, respectively, provided that they are photolyzed at 40 °C in the presence of 1 equiv of the corresponding disulfide or diselenide. Trifluoromethyl sulfides or selenides are obtained, and the added disulfide (or diselenide) is recovered after reaction. In such a way, S-(trifluoromethyl)cysteine derivatives can be obtained.