A theoretical study of the formation of phosphaacetylene by thermolysis of triallylphosphine

A theoretical study of the decomposition of triallylphosphine into phosphaacetylene at the B3LYP/6-311++G(3df,2p) level has shown that the most likely mechanism involves two retroene eliminations of propene leading to vinylphosphaacetylene. Two mechanisms can account for the formation of HCP from vinylphosphaacetylene, either by a 1,2 or a 1,3 hydrogen shift. The first pathway was found to be the most favored kinetically. It is quite similar to the pathway proposed for the thermal decomposition of vinylacetylene into acetylene in the shock tube.