Rearrangement of bis(alkylidynyl)phosphines to phospha-acyls

Abstract

A range of bis(alkylidynyl)phosphines RP{CM(CO)₂(Tp*)}₂ (M = Mo, W; R = Cl, Ph, Cy; Tp* = hydrotris(dimethylpyrazolyl)borate) are obtained from the reactions of [M(CLi)(CO)₂(Tp*)] with Cl₂PR or alternatively via the palladium(0)-mediated reactions of [W(CBr)(CO)₂(Tp*)] with RPH₂ (R = Py, Cy). The complexes RP{CW(CO)₂(Tp*)}₂ rearrange slowly (R = Cl) or on heating (R = Ph) to afford the isomeric phospha-acyls [W₂(μ:η¹-C;η²-C,P-CCPR)(CO)₄(Tp*)₂].