Synthesis of trisphaeridine and norchelerythrine through palladium-catalyzed aryl-aryl coupling reaction

Total syntheses of trisphaeridine (3) and norchelerythrine (4), fully aromatized benzo[c]phenanthridine alkaloids, were accomplished via the internal aryl-aryl coupling reaction of halo amides protected by a methoxymethyl group with the palladium reagent, followed by reduction with lithium aluminium hydride and treatment with hydrochloric acid.