Synthesis and reactivity of acylphosphine tetracarbonyl-iron complexes

A general method for the synthesis of (CO)(4)Fe[PPhX(C(O)R)] complexes from lithium acylferrates and PhXPCl is described (R = alkyl, phenyl, X = Ph, C l). The X-ray crystal structure of (CO)(4)Fe[PPh2(C(O)Me)] has been determi ned and compared with that of other mononuclear acylphosphine complexes, wh ich all possess a long P-C(O) bond. The weakness of this bond is revealed i n nucleophilic and basic media, where (CO)(4)Fe[PPh2(C(O)R)] mostly leads t o the [(CO)(4)FePPh2](-) anion. In the presence of LDA, however, some depro tonation occurs for R = Me, n-Bu, and subsequent addition of Ph2PCl leads t o monodentate alpha-phosphinoxyvinyl phosphine carbonyliron complexes in mo derate yield. (C) 1999 Elsevier Science S.A. All rights reserved.