M. Basato et al., Metal-catalysed synthesis of nitroenaminones from alpha-nitroketones or -esters and nitriles, J MOL CAT A, 139(2-3), 1999, pp. 121-130
Transition metal(II) carbonylnitronates or acetates selectively catalyse th
e carbon-carbon bond formation reaction between benzoylnitromethane and met
hyl (or ethyl) nitroacetate with electrophilically activated nitriles to fo
rm 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 bas
ic conditions in which compounds 3 are unstable. The proposed mechanism, wh
ich implies coordination of the O2NCHCOR- moiety and nucleophilic attack of
the metal-chelate to the nitrile carbon atom, is supported by the successf
ul synthesis of the intermediate complex [Ni{O2N(MeOCO)CC(CCl3)NH}(2)(H2O)(
2)]. (C) 1999 Elsevier Science B.V. All rights reserved.