Reduction of carbene adducts of carbon disulfide: Novel access to 1,1-dithiolates

The carbene adducts 5a,b react with two equivalents of potassium to form the I,l-dithiolate salts 6a,b which are converted into the olefins 7a,b on treatment with iodomethane. On further reaction with excess iodomethane the imidazolium salts 8a,b are obtained. 7b reacts with iodine to form the cationic dithiocarboxylic ester 9b. Electrochemical reduction of 5b las investigated by cyclic voltammetry and chronocoulometry) proceeds through a stepwise ECEC reaction mechanism to a dianion which undergoes a follow-up reaction. The rather negative values of redox potentials (E-1(0) = -2.51 V, E-2(0) = -2.43 V vs, ferrocene) confirm the influence of the ir-electron distribution.