Alkali-Metal-Mediated Coupling of a Phosphorus-Substituted Alkene. Structural Characterization of Dilithium 1,1,4,4-Tetrakis(diphenylphosphino)butane-1,4-diide

The butane-1,4-diide salt {(THF)2Li(Ph2P)2CCH2}2 is obtained by treatment of (Ph2P)2CCH2 with lithium in THF; hydrolysis of this salt yields the novel tetraphosphine {(Ph2P)2CHCH2}2.