Intramolecular palladium-catalyzed cyclization of methyl 1-(2-bromobenzyl)indole-2-carboxylates: Synthesis of pratosine and hippadine

Abstract Palladium-catalyzed cyclization of methyl 1-(2-bromo-4,5-dimethoxy-benzyl)indole-2-carboxylate in the presence of potassium acetate in hot 1,4-dioxane gave a 7 H -pyrrolo[3,2,1- de ]phenanthridine derivative, which was converted to pratosine in four steps. In a similar manner, hippadine was also prepared.