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

Trifluorothioacetates (CF 3 CO−S−R, from (CF 3 CO) 2 O and thiols) as well as trifluoromethanethio- or trifluoromethaneselenosulfonates (CF 3 SO 2 −Y−R; Y = S, Se; from CF 3 SO 2 Na, RYYR, and Br 2 ) 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.