Construction of 9H‑Pyrrolo[1,2‑a]indoles by a Copper-Catalyzed Friedel–Crafts Alkylation/Annulation Cascade Reaction

An efficient and concise Cu­(OTf)2-catalyzed Friedel–Crafts alkylation/annulation cascade reaction of substituted indoles with 1,2-dicarbonyl-3-enes has been established. This reaction uses readily available starting materials and is operationally simple, thus representing a practical method for the construction of diverse 9H-pyrrolo­[1,2-a]­indoles bearing a carbonyl group.