Two new sterically protected 3, 4-diphosphinidenecyclobutenes, ie, 1, 2-bis [4-(4- methylphenyl) butyl]-3, 4-bis [(2, 4, 6-tri-t-butylphenyl) phosphinidene] cyclobutene, and 3, 4- bis [(2, 4, 6-tri-t-butylphenyl) phosphinidene]-1, 2-bis [4-(4-vinylphenyl) butyl] cyclobutene, were prepared. Copolymerization of the latter with styrene was studied. Treatment of [6-(4- vinylphenyl) hex-1-ynyl](2, 4, 6-tri-t-butylphenyl) phosphine with butyllithium and 1, 2- ...
