Synthesis of (E)‐1,2‐Diphosphanylethene Derivatives from Alkynes by Radical Addition of Tetraorganodiphosphane Generated In Situ

E-asy radical addition: A tetraorganodiphosphane, generated in situ from a diorganophosphane and a chlorodiorganophosphane in the presence of triethylamine, adds to terminal alkynes by a radical process (see scheme) to afford (E)-diphosphanylethene derivatives in excellent yields. The reaction conditions are mild enough to tolerate many functional groups.