Cu(I)-Catalyzed Chemoselective and Stereoselective [3 + 3] Cycloaddition of Azomethine Ylides with 2-Indolylnitroethylenes: Facile Access to Highly Substituted Tetrahydro-γ-Carbolines

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• 作者：Wu-Lin Yang ; Chun-Yan Li ; Wen-Jing Qin ; Fei-Fei Tang ; Xingxin Yu ; Wei-Ping Deng
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：September 2, 2016
• 年：2016
• 卷：6
• 期：9
• 页码：5685-5690
• 全文大小：394K
• 年卷期：0
• ISSN：2155-5435

文摘

A Cu(I)-catalyzed asymmetric [3 + 3] cycloaddition of azomethine ylides with 2-indolylnitroethylenes is described. Challenges confronted in this reaction include chemoselectivity between [3 + 2] cycloaddition and [3 + 3] cycloaddition, reactivity and stereoselectivity of intramolecular Friedel–Crafts reaction, and enantioselective control for constructing tetrahydro-γ-carbolines bearing multiple stereocenters. In the presence of copper(I)/Ph-Phosferrox complex, an array of chiral tetrahydro-γ-carboline compounds was generally obtained in moderate to high yields (up to 92%) with moderate to high chemoselectivities (up to 94:6 cr) and a high level of stereoselectivity (up to >98:2 dr, >99% ee in most cases). [Here, cr is the chemoselectivity ratio, dr is the diastereoisomeric ratio, and ee is enantiomeric excess.]