Rhodium‐Catalyzed Successive [3 + 2]/[4 + 2] Annulation of 2‐(Acetylamino)pyridines With Alkynes to Construct Tetracyclic Pyridopyrroloisoquinoline Frameworks

The rhodium‐catalyzed double dehydrogenative annulation of 2‐(acetylamino)pyridines with two molecules of diarylacetylenes through deacetylation proceeds smoothly to produce pyrido[3′,2′:4,5]pyrrolo[2,1‐ a ]isoquinoline derivatives. The annulation method provides a straightforward synthetic route to tetracyclic or pentacyclic fused heteroarenes from simple, readily available substrates.