Treatment of allylic alcohols with thiocarbonyldiimidazole generates an unstable O-allyl imidazolyl thione ester, which rearranges spontaneously and in high yield to
the corresponding S-allyl imidazolyl thiol ester. Displacement of the imidazole by N-alkylanilines in the presence of a nucleophilic catalyst (HOBt or ECHIA) gives S-allyl N-aryl thiocarbamates in excellent yields (up to 97%) over two steps.
Key words
sigmatropic rearrangement - thiocarbamates - alcohols - stereospecificity - sulfur