Synthesis and reactivity of acylphosphine tetracarbonyl–iron complexes

Abstract

A general method for the synthesis of (CO) 4Fe[PPhX(C(O)R)] complexes from lithium acylferrates and PhXPCl is described (R=alkyl, phenyl, X=Ph, Cl). The X-ray crystal structure of (CO) 4Fe[PPh 2(C(O)Me)] has been determined and compared with that of other mononuclear acylphosphine complexes, which all possess a long P–C(O) bond. The weakness of this bond is revealed in nucleophilic and basic media, where (CO) 4Fe[PPh 2(C(O)R)] mostly leads to the [(CO) 4FePPh 2] − anion. In the presence of LDA, however, some deprotonation occurs for R=Me, n-Bu, and subsequent addition of Ph 2PCl leads to monodentate α-phosphinoxyvinyl phosphine carbonyliron complexes in moderate yield.