Reaction of 2,2′‐bis( N ‐methylindolyl) with dimethyl acetylenedicarboxylate and thermally‐ and photochemically‐induced cyclizations of the product

2,2′‐Bis( N ‐methylindolyl) 1 reacts with dimethyl acetylenedicarboxylate to furnish the 3‐dimethyl maleoyl‐substituted 2,2′‐bisindolyl 2 . Compound 2 cyclizes under aluminum trichloride catalysis according to a polar process to give a cyclopenta[2,1‐ b :3,4‐ b ′]diindole derivative 4 . Reaction of compound 4 with benzyl‐amine yields the spiro derivative 5 . Photochemically‐induced 1,6‐electrocyclization of compound 2 gives rise to the indolo[2,3‐ a ]carbazole 6 directly, which is readily transformed to the pyrrolo‐annelated carbazole 7 by treatment with benzylamine.