Efficient synthesis of polyfunctionalized thiophene-2,3-diones and thiophen-3(2H)-ones using β-oxodithioestersElectronic supplementary information (ESI) available. CCDC 1402849 and 1402850. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5ra11629e

Efficient methods for the preparation of polyfunctionalized thiophene-2,3-diones and thiophen-3(2 H )-ones using β-oxodithioesters were described. In this study, β-oxodithioesters were found to react directly with oxalyl chloride producing 4-aroyl-5-(methylthio)thiophene-2,3-diones in 96-98% yields. However, β-oxodithioesters were found to react efficiently with chloroacetic anhydride in the presence of a base catalyst such as DMAP, which gave 4-aroyl-5-(methylthio)thiophen-3(2 H )-ones in 61-77% yields. Efficient methods for the preparation of polyfunctionalized thiophene-2,3-diones and thiophen-3(2 H )-ones using β-oxodithioesters were described.