First isolation of 1,2-dithietan-3-one from α-dithiolactone

Treatment of α-dithiolactone 6 with ethoxycarbonylformonitrile oxide 7 resulted in the formation of 1,2-dithietan-3-one 4. Compound 4a was oxidized with m-CPBA to give 4,4-di-tert-butyl-1,2-dithietan-3-one 1-oxide 5a. The reaction of 4a with triphenylphosphine afforded the corresponding α-thiolactone 10.