Metal-catalysed Synthesis of Nitroenaminones from a-Nitroketones or -esters and Nitriles.

Transition metal(II) carbonylnitronates or acetates selectively catalyse the carbon-carbon bond formation reaction between benzoylnitromethane and methyl (or ethyl) nitroacetate with electrophilically activated nitriles to form the nitroenaminones O2N(RCO)C=C(R')NH2 3a-d in high to medium yields (73-50%; a: R = Ph, R'= CCl3; b: R = MeO, R'= CCl3; c: R = EtO, R'= CCl3; d: R = MeO, R' = EtOCO). The use of metal catalysts permits of avoiding the basic conditions in which compounds 3 are unstable. The proposed mechanism, which implies coordination of the O2NCHCOR- moiety and nucleophilic attack of the metal-chelate to the nitrile carbon atom, is supported by the successful synthesis of the intermediate complex [Ni{O2N(MeOCO)CC(CCl3)NH}(2)(H2O)(2)].