The Regioselective Functionalization Reaction of Unprotected Carbazoles with Donor-Acceptor Cyclopropanes
The Regioselective Functionalization Reaction of Unprotected Carbazoles with Donor-Acceptor Cyclopropanes
复制标题
未保护的咔唑与供体-受体环丙烷的区域选择性官能化反应
DOI：
10.1021/acs.joc.1c00494
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发表时间：
2021
影响因子：
3.6
通讯作者：
Zhao Yufen
中科院分区：
文献类型：
--
作者：
Zhao Hua;Shen Peng;Sun Dongru;Zhai Hongbin;Zhao Yufen
首次证明了未保护的咔唑与给体-受体（D-A）环丙烷的区域选择性官能化反应。以Sc（OTf）3为刘易斯酸催化剂，咔唑的N-H官能化反应通过高选择性的氮引发亲核开环反应进行。值得注意的是，通过使用TfOH作为布朗斯台德酸催化剂，通过Friedel-Crafts型加成在未保护的咔唑的3位进行直接的C-H官能化。该策略有利于含咔唑杂环化合物的多样性合成，拓展了D-A环丙烷的新应用。
The regioselective functionalization reaction of unprotected carbazoles with donor–acceptor (D–A) cyclopropanes has been demonstrated for the first time. With Sc(OTf)3as Lewis acid catalyst, the N–H functionalization of carbazoles takes place through a highly selective nitrogen-initiated nucleophilic ring opening reaction. Significantly, by engaging TfOH as Brønsted acid catalyst, a straightforward C–H functionalization at the 3-position of the unprotected carbazole proceeds via Friedel–Crafts-type addition. This strategy facilitates the diversity-oriented synthesis of carbazole-containing heterocycles and expands the novel application of D–A cyclopropanes.