Copper(II)-Catalyzed Synthesis of Pyrrolo[3,4- b ]quinolinediones from o -Amino Carbonyl Compounds and Maleimides.

A copper(II)-catalyzed cascade synthesis of 1 H -pyrrolo[3,4- b ]quinoline-1,3(2 H )-diones has been achieved from readily available o -amino carbonyl compounds and maleimides. This one-pot cascade strategy involves a copper-catalyzed aza-Michael addition followed by condensation and oxidation to deliver the target molecules. The protocol features a broad substrate scope and excellent functional group tolerance and affords products in moderate to good (44-88%) yields.