Synthesis of (4-arylpyrrolidin-2-ylidene) derivatives of cyclic β-dicarbonyl compounds from cinnamoyl precursors

1,4-Conjugate Michael addition of nitromethane to the enone fragment of cinnamoyl derivatives of carbo- and heterocyclic β-dicarbonyl compounds provided the corresponding nitromethyl derivatives. The chemoselective reduction of the nitro group in the latter afforded 4-arylpyrrolidin-2-ylidene derivatives of β-dicarbonyl compounds in high yield. The reaction products with the heterocyclic β-dicarbonyl fragment are formed as equilibrium mixture of E- and Z-rotamers in which the E-rotamer predominates.