Generation of 2-lithio-2-(methylthio)-1,3-benzodithioles, new carboxyl carbanion equivalents, and their application to the syntheses of unsymmetrical hexathioorthooxalates

2-Lithio-2-(methylthio)-1,3-benzodithioles are readily generated either by thiophilic addition of methyllithium to o-phenylenetrithiocarbonates or by deprotonation of 2-(methyl-thio)-1,3-benzodithioles with n-butyllithium in THF; these anions are protonated (aqueous NH4Cl) or methylated (MeI) as expected, but undergo an unexpected, overall carbophilic addition reaction with cyclic trithiocarbonates to yield, after alkylation, unsymmetrical hexathioorthooxalates, compounds which have been difficult to prepare by traditional methods. © 1984.