The pathway for the aqueous chlorinolysis of a series of β-sulfonyl-sulfides is elucidated and the SN2 cleavage step examined. Steric effects in the cleavage of the α-polychloro- oxochloro-sulfonium chloride intermediates are held to be responsible for the suppression of the established nucleophilic competition between water molecules and chloride ions with the result that all cleavage products arise from nucleophilic attack by chloride ions. This ...