Electrochemical oxidation of ketenedithioacetals

Anodic oxidation of ketenedithioacetals 1, (RRC)-R-1-C-2=C(SMe)(2), is reported in this work. Cyclic voltammetry performed in dry MeCN 0.1 M NaClO4 using Pt bead as anode and Ag/AgI as reference electrode showed an irreversible oxidation step. The corresponding oxidation peak potentials were slightly dependent on the carbon-carbon double bond substitution pattern (tri- vs. tetrasubstitution) but showed a strong dependence upon the nature of the R groups. The main products of the controlled potential preparative electrolyses in 0.2 M NaClO4 aqueous acetonitrile were dimers for R-1 = n-Pr or C6H5C(O) and R-2 = H, and alpha-hydroxy-thioesters and monosulfoxides for the substrates with tetrasubstituted carbon-carbon double bonds.