Trifluoromethanesulfinyl Chloride for Electrophilic Trifluoromethythiolation and Bifunctional Chlorotrifluoromethythiolation

Trifluoromethanesulfinyl chloride (CF 3 SOCl) has been introduced as a new reagent for C−H trifluoromethylthiolation of indoles, thiophenes, and ketones under catalyst‐free conditions and in the absence of reductant. The disproportionation of CF 3 SOCl to CF 3 SO 2 Cl and CF 3 SCl provides two pathways for the trifluoromethylthiolation. Direct trifluoromethylthiolation with CF 3 SCl or trifluoromethylsulfoxidation with CF 3 SOCl is followed by reduction with CF 3 SOCl. This reagent can be used to functionalize benzothiophenes, benzofurans, and indenes under the promotion of Ag 2 CO 3 . It can also be used for trifluoromethylthiolation of thiols and benzeneselenols, and 1,2‐bifunctional chlorotrifluoromethylthiolation of indoles, styrenes, and alkyenes. The method can also be extended for difluorometylthiolation reactions using CF 2 HSOCl.