Photolysis of dibenzyl-Δ3-1, 3, 4-oxadiazolines (3) in the presence of dimethyl acetylenedicarboxylate (DMAD) gives only modest yields of the expected symmetrical 3, 3- dibenzylcyclopropenes (4), but these are accompanied by more than six by-products, including unsymmetrical cyclopropenes, methylenecyclopropanes, and various pyrazoles. The origin of this array of products can be explained by a series of steps starting with ...
