Rhodium-Catalyzed Oxidative Annulation of 2- or 7-Arylindoles with Alkenes/Alkynes Using Molecular Oxygen as the Sole Oxidant Enabled by Quaternary Ammonium Salt |
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| Authors: | Weihui Zhuang Jiaqi Zhang Yanping Zheng Qiufeng Huang |
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| Affiliation: | 1.Fujian Key Laboratory of Polymer Materials, College of Chemistry & Materials Science, Fujian Normal University, Fuzhou 350007, China; (W.Z.); (J.Z.); (Y.Z.);2.Fujian Provincial Key Laboratory of Advanced Materials Oriented Chemical Engineering, Fuzhou 350007, China |
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| Abstract: | Developing an efficient catalytic system using molecular oxygen as the oxidant for rhodium-catalyzed cross-dehydrogenative coupling remains highly desirable. Herein, rhodium-catalyzed oxidative annulation of 2- or 7-phenyl-1H-indoles with alkenes or alkynes to assemble valuable 6H-isoindolo[2,1-a]indoles, pyrrolo[3,2,1-de]phenanthridines, or indolo[2,1-a]isoquinolines using the atmospheric pressure of air as the sole oxidant enabled by quaternary ammonium salt has been accomplished. Mechanistic studies provided evidence for the fast intramolecular aza-Michael reaction and aerobic reoxidation of Rh(I)/Rh(III), facilitated by the addition of quaternary ammonium salt. |
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| Keywords: | rhodium catalysis oxidative annulation 2- or 7-arylindoles molecular oxygen quaternary ammonium salt |
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