Efficient aerobic and DMSO-oxidative sulfenylation reactions catalyzed by Na2S2O3

Abstract

Two efficient acid-base-free procedures are introduced for the sulfenylation of cyclic enaminone compounds under aerobic and DMSO-oxidative conditions catalyzed by Na2S2O3. According to procedures, a mixture of an aryl thiol and a cyclic enaminone are reacting together in DMF (aerobic oxidative conditions) or DMSO in the presence of a catalytic amount of Na2S2O3 (0.1 equiv in DMSO and 0.4 equiv in DMF) to produce the related α-sulfenylated cyclic enaminone compound in high yields. Both reactions are not satisfactory in the absence of Na2S2O3, so the reaction in DMF (aerobic condition) does not produce any product at all and the conversion in DMSO progresses by less than 50% within 24 h.