The reaction of potassium tetracarbonylhydridoferrate with ethyl acrylate in ethanol

Article abstract of DOI:10.1016/0022-328X(89)85115-0

The reaction of KHFe(CO)4 with an excess of ethyl acrylate in ethanol for 30 h at 70 deg C leads to ethyl propyonate (270percent with respect to iron) and diethyl 4-oxopimelate (40percent yield with respect to iron), whether in an atmosphere of CO or argon.These reactions are shown to proceed by regioselective addition of KHFe(CO)4, to ethyl acrylate to give an intermediate alkyl tetracarbonylferrate 2 (M=K), which has been isolated as the PPN⁺ salt.In situ protonation of 2 (or of the isomeric alkyltetracarbonylferrate 10) by the solvent, and reductive elimination of ethyl propionate generate a coordinatively unsaturated Fe(CO)4 species which, when quenched in situ, gives the corresponding Fe(CO4)(acrylate) complex 9.In the presence of K2CO3 and an excess of ethyl acrylate, 9 affords ethyl propionate in 120percent yield with respect to iron, which is consistent with observed pseudo-catalytic reduction of ethyl acrylate by KHFe(CO)4.The formation of diethyl oxopimelate is thought to involve the isomerisation of 2, followed by reaction of the resulting alkyltetracarbonylferrate 10 with ethyl acrylate.