Copper-Catalyzed Tandem Synthesis of Indolo‑, Pyrrolo[2,1‑a]isoquinolines, Naphthyridines and Bisindolo/Pyrrolo[2,1‑a]isoquinolines via Hydroamination of ortho-Haloarylalkynes Followed by C‑2 Arylation

An efficient approach for the copper-catalyzed regioselective tandem synthesis of diversely substituted indolo­[2,1-a]­isoquinolines 11a–r, pyrrolo­[2,1-a]­isoquinolines 12a–d, and indolo-, pyrrolo­[2,1-f]­[1,6]­naphthyridines 14a–f via preferential addition of the heterocyclic amines onto the ortho-haloarylalkynes over N-arylation followed by intramolecular C-2 arylation is described. The scope of the developed chemistry was successfully extended for the direct synthesis of bisindolo-, pyrrolo­[2,1-a]­isoquinolines 15a–g, a regioisomer of the bisindolo­[1,2-a]­quinolines used as organic single-crystal field-effect transistor. Hydroxymethyl benzotriazole, which is an inexpensive and air stable compound, has been used as a ligand to carry out this one-step conversion of simple, readily available starting materials into an interesting class of heterocyclic compounds.