O-Octadecyl-S-trifluorothiolcarbonate is a cheap and storable crystalline source of trifluoromethanethiol that can be prepared in two steps on a multigram scale from trifluoroacetic anhydride and sodium O-octadecyl-dithiocarbonate (xanthate). It reacts directly with gramines or with α-bromoketones and -esters in the presence of KF and pyrrolidine to give the corresponding trifluoromethyl sulfides in generally high yield.