Convenient synthesis of dithiafulvene carbene complexes as potential precursors of extended TTF

The condensation of α-carbanion of Fischer-type carbene complex with 2-thiomethyl-1,3-dithiolium salts 1 gave new heterocyclic organometallic carbenes 2 potentially precursors of extended TTF. Reaction of allylic carbanion 4 derived from (methoxypropenyl)pentacarbonyl carbene complex afforded a mixture of monoheterocyclic condensation products 7 and diheterocyclic carbene complexes 8 produced from successive α and γ attacks of the heterocyclic cations.