A Facile, high-yield synthesis of trans-Fe(CO)3(PR3)2 from Fe(CO)5, Fe(CO)4CHO-, HFe(CO)4-, or HFe(CO)3PR3-

Article abstract of DOI:10.1021/om00102a006

The reaction of Fe(CO)₅ with PR₃ and NaBH₄ in refluxing n-butyl alcohol affords high yields of trans-Fe(CO)₃(PR₃)₂. It has been shown that Fe(CO)₄PR₃, which does not appear in the collected product, is also not a significant intermediate in the reaction. The reaction proceeds by initial formation of H₂ gas and Fe(CO)₄CHO^-. The formyl complex decomposes to HFe(CO)₄^- which reacts with PR₃ to give the disubstituted product. The principal intermediate for this substitution is believed to be HFe(CO)₃PR₃^-, although polynuclear species may also be important. The substitution of HFe(CO)₄^- by PR₃ is favorable when the counterion is Na⁺ but not when it is PPN⁺. The overall reaction is very sensitive to choice of solvent; substitution of ethanol for n-butyl alcohol leads to greatly reduced yields.