κ1- and κ2-Complexes of Fluorenylidene–Allenyl Phosphines and Phosphine Oxides with Palladium Chloride and Iron Carbonyl: Displacement of Trimethylsilyl by Diphenylphosphino via a Stabilized Carbanion

An attempt to prepare 3,3-(biphenyl-2,2′-diyl)-1-diphenylphosphino-1-(trimethylsilyl)allene, 15, by treatment of 3,3-(biphenyl-2,2′-diyl)-1-lithio-1-(trimethylsilyl)allene with chlorodiphenylphosphine led instead to 3,3-(biphenyl-2,2′-diyl)-1,1-bis(diphenylphosphino)allene, 14. The proposed mechanism invokes attack on the trimethylsilyl group in 15 by liberated chloride to form a stabilized anion that reacts with a second molecule of the …