Opening of thiirane ring by hydrogen halides

Abstract

A study was made of the reactions that proceed in the systems: THF-hydrogen halide-acetic anhydride and ethylene sulfide-hydrogen halide-acetic anhydride. The cleavage of the THF ring most probably proceeds via the step of forming carbonium ions. The data on the transformations of ethylene sulfide are in agreement with the concepts of bi- and trimolecular processes for the cleavage of either the episulfonium ring or the activated thiirane ring by either hydrogen halide or halide anion from the state of an intimate ion pair.