Cyanation of indoles with benzyl cyanide as the cyanide anion surrogate
作者:Lianpeng Zhang、Qiaodong Wen、Jisong Jin、Chen Wang、Ping Lu、Yanguang Wang
DOI:10.1016/j.tet.2013.03.089
日期:2013.5
A copper-mediated direct cyanation of indoles with benzyl cyanide as the cyanideanion surrogate has been achieved. The cascade reaction furnished 3-cyanoindoles under mild reaction conditions in good to excellent yields with various functional groups tolerance.
GaCl<sub>3</sub>-Catalyzed C–H Cyanation of Indoles with <i>N</i>-Cyanosuccinimide
作者:Xue Wang、Mohamed Makha、Shu-Wei Chen、Huaiji Zheng、Yuehui Li
DOI:10.1021/acs.joc.9b00416
日期:2019.5.17
An efficient GaCl3-catalyzed direct cyanation of indoles and pyrroles using bench-stable electrophilic cyanating agent N-cyanosuccinimide was achieved and afforded 3-cyanoindoles and 2-cyanopyrroles in good yields and excellent regioselectivities. Notably, this protocol exhibited high reactivity for unprotected indoles and was applicable to a broad range of indole and pyrrole substrates.
A copper-promoted C3-cyanation of both the free N–H and N-protected indoles by N,N,N′,N′-tetramethyl-ethane-1,2-diamine (TMEDA) and ammonium is achieved. The iminium ion acts as the intermediate in this transformation, which is sequentially electrophilically attacked by indole and H2O followed by hydrolyzation to form the aldehyde. Then the reaction between the aldehyde and ammonium afforded nitriles. The reaction employs O2 as a clean oxidant with good efficiency and functional group tolerance. Thus, it represents a facile and safe procedure leading to 3-cyano indoles.