Allylation of N-unsubstituted isatin N,N'-cyclic azomethine imines with Morita-Baylis-Hillman carbonates in the presence of 1-10 mol% DABCO in DCM at room temperature, rapidly gave N-allylated and N, β-diallylated isatin N,N'-cyclic azomethine imine 1,3-dipoles in moderate to high yields. The reaction features mild reaction conditions, easily practical operation, and short reaction times in most cases. Furthermore, the alkylated products were transformed into novel bicyclic spiropyrrolidine oxoindole derivatives through the [3+2] or [3+3]-cycloaddition with maleimides or Knoevenagel adducts.
Keywords: MBH carbonate; allylation; azomethine imine; cycloaddition; dipole.