Iron-Catalyzed Trifluoromethylation of Indole-Tethered Alkene Enables Synthesis of CF3-Containing Spiroindolenines and Tetrahydrocarbazoles |
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Authors: | Yilin Zhao Tingting Hou Liming Zhang Xue Wang Jingli Hou Yangping Liu Guifang Han Yuguang Song |
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Affiliation: | Tianjin Key Laboratory of Technologies Enabling Development of Clinical Therapeutics and Diagnostics School of Pharmacy, Tianjin Medical University, No 22.Qixiangtai Rd., Heping Dist, Tianjin, 300070 P.R. China |
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Abstract: | An iron-catalyzed trifluoromethylation of indole-tethered alkene with Togni's reagent to construct CF3-containing spiro[indole-3,3′-pyrrolidine] and tetrahydrocarbazole derivatives under mild and convenient conditions has been disclosed. Mechanistic studies indicate that the reaction proceed through a CF3 radical addition to the alkene, followed by sequential dearomatizing spiocyclization of the indole and oxidation to afford the spiro[indole-3,3′-pyrrolidine] derivatives. Meanwhile, when the substituent at the C2 position of the indole is hydrogen, the CF3-containing tetrahydrocarbazole is obtained through trifluoromethylation of alkene and cyclization of indole. |
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Keywords: | dearomatization iron radical reaction spirocarbocycle trifluoromethylation |
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