The reduction of phosphate esters to alkynes with various reducing agents

Bis-(diethylphosphoro)-stilbene was used as a model compound to test the reductive Selectivities of various reducing agents. In the experiments performed, it was shown that titanium metal in THF and sodium amalgam in THF/DMSO provided the greatest selectivity for preparing diphenyl- acetylene from bis-(diethylphosphoro)-stilbene. Some of the reducing agents gave a more statistical mixture of reduction products while other afforded only dubious results. It was found that non aromatic phosphate esters failed to give any substantial amount of the expected products.