Treatment of alkanesulfinyl chlorides having α-hydrogens with tertiary amine bases gives thiocarbonyl S-oxides (sulfines) as isolable compounds. Thus, treatment of n-propanesulfinyl chloride with triethylamine gives syn-propanethial-S-oxide, the lachrymatory agent of the onion. Treatment of methanesulfinyl chloride or ethane-1,2-bis-sulfinyl chloride, (prepared by oxidative chlorination of 1,2-ethanedithiol, HSCH2CH2SH), with a tertiary amine in the presence of the chiral glucose-derived secondary alcohol diacetone-D-glucose affords optically pure sulfinate esters by a process of Dynamic kinetic resolution. Sulfinyl chlorides undergo Friedel–Crafts reactions with arenes giving sulfoxides.
