Addition of Thiols to Isocyanates Catalyzed by Simple Rare-Earth-Metal Amides: Synthesis of S-Alkyl Thiocarbamates and Dithiocarbamates

Simple additions of thiols to isocyanates/isothiocyanates under mild conditions led to the efficient preparation of various S-alkyl thiocarbamates and dithiocarbamates, respectively. The lanthanum complex La[N(SiMe3)2]3 was found to be active to give thiocarbamates and dithiocarbamates in medium to excellent yields with a good group tolerance. A plausible mechanism of the catalytic transformation was proposed on the basis of both experimental observations and DFT calculations.