title: Intramolecular Csp2-Csp2Friedel-Crafts Arylation: Substrate- and Condition-Controlled Divergent Synthesis of Fused-β-carbolines.
abstract: A triple cooperative catalysis-mediated multicomponent reaction between 1-formyl-N-substituted-β-carbolines, a terminal alkyne, and a secondary amine allows access to unprecedented polycyclic β-carbolines via sequential A3-coupling and an intramolecular Csp2-Csp2Friedel-Crafts arylation reaction. The reaction is successful in a dry inert atmosphere only with substrates bearing a methoxy-substituted benzyl group at the indole nitrogen. Conversely, treating 3-aminoindolizino[8,7-b]indoles (obtained after A3-coupling) with acid in the presence of H2O in air offers a general route to natural-alkaloid-like products.
authors.forename: Shashikant U
authors.initials: SU
authors.lastname: Dighe
authors.forename: Veena D
authors.initials: VD
authors.lastname: Yadav
authors.forename: Rohit
authors.initials: R
authors.lastname: Mahar
authors.forename: Sanjeev K
authors.initials: SK
authors.lastname: Shukla
authors.affiliation: Academy of Scientific and Innovative Research, New Delhi-110025, India.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Batra