Michael addition of N-bonded enolato ligands to acrylonitrile in iron and ruthenium complexes

Treatment of the N-bonded enolatoiron(II) complex [M(H)(NCCHCO2R)(L)2] [1a, M = Fe, R = Me, L = depe {1,2-bis(diethylphosphino)ethane}; 1b, M = Fe, R = Et, L = depe; 2, M = Ru, L = dppe] with acrylonitrile results in mono-Michael addition to give [M(H){NCC(C2H4CN)CO2R}(L)2 ], which is found to be an active intermediate for the catalytic double-Michael reaction of cyanoacetate with acrylonitrile.