[4 + 2] Annulation of 3-Nitroindoles with Alkylidene Malononitriles: Entry to Substituted Carbazol-4-amine Derivatives

作者：Dongdong Cao, Anguo Ying, Hanjie Mo, Dingben Chen, Gang Chen, Zhiming Wang, Jianguo Yang · 发表于：The Journal of Organic Chemistry · 年份：2018 · DOI：10.1021/acs.joc.8b01876 · 被引用次数：44 · 研究领域：Catalytic C–H Functionalization Methods、Sulfur-Based Synthesis Techniques、Synthesis and Biological Evaluation

A general and transition-metal-free method for the construction of the carbazol-4-amine motif via a vinylogous Michael addition/cyclization/isomerization/elimination reaction of 3-nitroindoles with alkylidene malononitriles has been developed. This novel methodology allows the facile synthesis of a series of di- and trisubstituted carbazol-4-amine derivatives in moderate to good yields. A gram-scale experiment was successfully performed, highlighting the practicability of this method. Moreover, this strategy is also applicable to 3-nitrobenzothiophene, affording the corresponding dibenzo[ b, d]thiophen-1-amine derivatives in moderate yields.