A study of the chemistry of tetrathioethylenes, now in progress, entailed the investigation of several methods for their synthesis.
The generation of sulfur stabilized carbenes is a well established route to these compounds 1 and we have successfully applied this method to the synthesis of tetrathiafulvalene (2.'
Other methods were necessary for the synthesis of tetrathioethylene 33 however, as Et3N S --CH3-CN [ 1 C) I: 1-W B the carbene f undergoes rapid and facile decomposition to ethylene and carbon disulfide. 4 These observations suggested: (a) that a low energy pathway (symmetry allowedj5exists between carbenes of type & and & and their C2 and CS2 components, (b) that carbene & is in a more favorable thermodynamic relationship to these components by virtue of resonance stabilization, and (c) that carbenes of type L might conceivably be generated by a cycloaddition reaction between carbon disulfide and acetylenes.
In view of possibility (c) a reaction between dimethyl acetylenedicarboxylate and carbon disulfide was sought with the following resultP A solution of the acetylene (5 g.) in carbon disulfide (200 ml) was heated under reflux for sixteen days.
During this time a crystalline precipitate formed and the solution became dark red. The cooled solution was decanted from the precipitate and, after evapo-