Addition of phosphorus–hydrogen and arsenic–hydrogen bonds to vinyl isocyanide

Abstract

Addition of diphenylphosphine or diphenylarsine to vinyl isocyanide catalysed by potassium t-butoxide gives the liquid 2-diphenylphosphinoethyl (I) or diphenylarsinoethyl isocyanide (II). However, a similar addition of phenylphosphine to vinyl isocyanide in tetrahydrofuran solution gives 4,5-dihydro-3-phenyl-1,3-azaphosphole rather than phenylphosphinediylbis(ethyl isocyanide). Reactions of compounds (I) and (II) with tetracarbonylnorbornadienechromium at room temperature give the yellow polymetal derivatives [Ph₂E·CH₂·CH₂·NC]₄Cr₃(CO)₁₂(E = P or As) rather than the simple monometal derivatives [Ph₂E·CH₂·CH₂·NC]Cr(CO)₄, in accord with the relative orientations of the two lone pairs in the ligand (I) or (II).