Palladium-Catalyzed C–H Bond Activation by Using Iminoquinone as a Directing Group and an Internal Oxidant or a Co-oxidant: Production of Dihydrophenanthridines, Phenanthridines, and Carbazoles

A palladium-catalyzed C–H bond activation reaction, via a redox-neutral pathway, for the preparation of dihydrophenanthridine, phenanthridine, and carbazole derivatives from biaryl 2-iminoquinones is developed. The preinstalled iminoquinone was designed to act as a directing group for ortho C–H acti...

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Bibliographic Details
Published in:Organic letters 2017-08, Vol.19 (15), p.4134-4137
Main Authors: Raju, Selvam, Annamalai, Pratheepkumar, Chen, Pei-Ling, Liu, Yi-Hung, Chuang, Shih-Ching
Format: Article
Language:English
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Summary:A palladium-catalyzed C–H bond activation reaction, via a redox-neutral pathway, for the preparation of dihydrophenanthridine, phenanthridine, and carbazole derivatives from biaryl 2-iminoquinones is developed. The preinstalled iminoquinone was designed to act as a directing group for ortho C–H activation and an internal oxidant or a co-oxidant. This catalysis proceeded through the following sequence: C–H bond activation, coordination and insertion of activated olefins, β-hydride elimination, H-shift, insertion, and protonation or β-hydride elimination. In addition, carbazoles can be prepared efficiently by using this method without the addition of external oxidants.
ISSN:1523-7060
1523-7052
DOI:10.1021/acs.orglett.7b01956