While for the reductive cleavage of a cyclopropane sigma-bond usually two lithium atoms are necessary, with the same amount of lithium two sigma-bonds of the ''butterfly olefin'' 4 are cleaved. On the way to 1,6-dilithio-3-hexyne (7) (1,3-dilithiopropylidene)cyclopropane (8) can be isolated provided that diethyl ether is used as the solvent.
While for the reductive cleavage of a cyclopropane sigma-bond usually two lithium atoms are necessary, with the same amount of lithium two sigma-bonds of the ''butterfly olefin'' 4 are cleaved. On the way to 1,6-dilithio-3-hexyne (7) (1,3-dilithiopropylidene)cyclopropane (8) can be isolated provided that diethyl ether is used as the solvent.