One-Pot Synthesis of Orange-Red Fluorescent Dimeric 2H-Pyrrolo[2,3-c]isoquinoline-2,5(3H)-diones from Benzamides and Maleimides via Ru(II)-Catalyzed Sequential C–C/C–N/C–C Bond Formation

We report here a direct and efficient strategy for the synthesis of highly conjugated dimeric pyrrolo-fused isoquinoline derivatives from readily available benzamides and maleimides. This reaction overall proceeds by following a domino approach: C–C bond formation via challenging primary amide-directed Ru(II)-catalyzed ortho alkenylation followed by annulation and C–C bond formation through Ru(II)-catalyzed dehydrogenative dimerization. The resulting products showed substituent-dependent tunable photoluminescence in the orange-red region with reasonably large Stokes shifts and interesting redox properties.