title: Cationic Cobalt(III) Catalyzed Indole Synthesis: The Regioselective Intermolecular Cyclization of N-Nitrosoanilines and Alkynes.
abstract: The unique regioselectivity and reactivity of cobalt(III) in the direct cyclization of N-nitrosoanilines with alkynes for the expedient synthesis of N-substituted indoles is demonstrated. In the presence of a cobalt(III) catalyst, high regioselectivity was observed when using unsymmetrical meta-substituted N-nitrosoanilines. Moreover, internal alkynes bearing electron-deficient groups, which are almost unreactive in the [Cp*Rh(III)]-catalyzed system, display good reactivity in this transformation.
authors.affiliation: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xue Yuan Rd. 38, Beijing, 100191, China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Liang
authors.affiliation: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Xue Yuan Rd. 38, Beijing, 100191, China. jiaoning@pku.edu.cn.|State Key Laboratory of Organometallic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, China. jiaoning@pku.edu.cn.
authors.forename: Ning
authors.initials: N
authors.lastname: Jiao
keywords: C−H activation; cobalt; indoles; reaction mechanisms; regioselectivity