Lithium 1-alkynethiolates, generated by a base-induced ring cleavage of 4-substituted 1,2,3-thiadiazoles, were efficiently converted into the corresponding sulfenate salts by mild oxidation using an N-sulfonyloxaziridine derived from pinacolone. In situ S-alkylation with alkyl halides led to α,β-acetylenic sulfoxides.