Acetylenes (1), carrying two bulky alkyl substituents, reacted with sulfur dichloride (ClSCl) to give 2, 3-dialkyl-2, 3-dichlorothiiranes (2) nearly quantitatively. The alkaline hydrolysis of crude 2 resulted in the formation of thiirene 1-oxides (3) in 68–90% yields based on 1, thus providing a convenient synthesis of 3.
