Copper-catalyzed site-selective S–S and C–C homocoupling of α-enolic dithioesters: straightforward and efficient access to 1,2-dithiols

Abstract

An operationally simple, economical, and practical new method for the synthesis of highly functionalized1,2-dithiols has been developed by copper catalyzed self-coupling ofa-enolic dithioesters via consecutiveformation of S–S and C–C bonds. Low-cost copper powder together with Ag2O as oxidant and promotercan be recycled at least four times with no loss of catalytic activity, making this strategy an ideal alter-native to existing methods. Notably, in situ formation of S,S0-bis(dithioacetal) as a reactive intermediatehas been proven, and the corresponding mechanistic insights are experimentally established.