A one-step access to the canthin-6-one architecture by the Baylis-Hillman reaction of methyl 1-formyl-9H-β-carboline-3-carboxylate or 1-formyl-9H-β-carboline involving an unprecedented cascade cyclization reaction is reported.

A copper-catalyzed efficient one step three component strategy for preparing a library of aminoindolizino[8,7-b]indoles from N-substituted 1-formyl-9H-β-carbolines, secondary amines, and substituted alkynes with high atom economy has been developed.

The chemistry of the Morita-Baylis-Hillman adducts of 1-formyl-β-carbolines has been extended for obtaining indolizino-indole derivatives which mimic the harmicine and homofascaplysin frameworks. Adducts of N-substituted methyl 1-formyl-9H-β-carboline-3-carboxylate yield indolizino-indole derivatives upon bromination followed by aqueous workup. On the other hand, N-substituted 1-formyl-9H-β-carbolines give rise to similar products in a one-pot DABCO-promoted

Substituted 1‐formyl‐9H‐β‐carbolines are demonstrated to be viable precursors for the synthesis of a library of new β‐carboline‐based polycyclic systems via 1,3‐dipolar cycloaddition strategy.

The synthesis of a variety of polycyclic quinolines is described. The target molecules were obtained in two steps by an initial reductive cyclization followed by another intramolecular cyclization in the allylamines afforded from either the acetates or allyl bromides of Baylis–Hillman adducts of 2‐nitrobenzaldehydes and acrylonitrile. The two steps proceeded in one‐pot for those substrates in which a formyl or hydroxy group reacted with the amino group of the 2‐aminoquinoline in the second intramolecular cyclization. In contrast, a basic medium was necessary for the second intramolecular cyclization reaction in substrates in which an alkoxycarbonyl group and the amino group participated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)