Brønsted Base Mediated Stereoselective Diphosphination of Terminal Alkynes with Diphosphanes.

A Brønsted base mediated stereoselective diphosphination of terminal alkynes with diphosphanes proceeds to deliver the corresponding (E)-1,2-diphosphinoethenes in good yields. The reaction of aromatic alkynes occurs efficiently in the presence of a catalytic amount of LiO-t-Bu while MN(TMS)2 (M = Li or Na) gave better results in the case of aliphatic substrates. The Brønsted base mediated protocol can offer a good alternative to precedented transition-metal-catalyzed or radical-promoted approaches to the 1,2-diphosphinoethene framework of potent interest in catalysis and coordination chemistry.