Intramolecular Csp2–Csp2 Friedel–Crafts Arylation: Substrate- and Condition-Controlled Divergent Synthesis of Fused-β-carbolines

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• 作者：Shashikant U. Dighe ; Veena D. Yadav ; Rohit Mahar ; Sanjeev K. Shukla ; Sanjay Batra
• 刊名：Organic Letters
• 出版年：2016
• 出版时间：December 2, 2016
• 年：2016
• 卷：18
• 期：23
• 页码：6010-6013
• 全文大小：423K
• ISSN：1523-7052

文摘

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 A<sup>3sup>-coupling and an intramolecular C<sub>sp<sup>2sup>sub>–C<sub>sp<sup>2sup>sub> Friedel–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 A<sup>3sup>-coupling) with acid in the presence of H<sub>2sub>O in air offers a general route to natural-alkaloid-like products.