Oxidative Cyclization of 2-Aryl-3-arylamino-2-alkenenitriles to N-Arylindole-3-carbonitriles Mediated by NXS/Zn(OAc)2
Qiao Yan, Ji Luo, Daisy Zhang-Negrerie, Hui Li, Xiuxiang Qi* and Kang Zhao*
*Tianjin Key Laboratory for Modern Drug Delivery & High-Efficiency, School of Pharmaceutical Science and Technology, Tianjin University, Tianjin 300072, P. R. China, Email: qxxzzu.edu.cn, combinologyyahoo.com
Q. Yan, J. Luo, D. Zhang-Negrerie, H. Li, X. Qi, K. Zhao, J. Org. Chem., 2011, 76, 8690-8697.
Various 2-aryl-3-arylamino-2-alkenenitriles give N-arylindole-3-carbonitriles in a one-pot manner through NBS- or NCS-mediated halogenation followed by Zn(OAc)2-catalyzed intramolecular cyclization. The process involves the formation of arylnitrenium ion intermediates, which undergo an electrophilic aromatic substitution to give the cyclized N-arylindoles.
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