Cobalt-Catalyzed Oxidant-Free Spirocycle Synthesis by Liberation of Hydrogen

The first example of oxidant-free cobalt-catalyzed synthesis of five-membered spirocycles is reported from benzimidates and maleimides utilizing nitrobenzene as promoter. In contrast to previously known cobalt-catalyzed oxidative C–H functionalization reactions, this transformation occurs efficientl...

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Bibliographic Details
Published in:Organic letters 2017-09, Vol.19 (17), p.4640-4643
Main Authors: Lv, Ningning, Liu, Yue, Xiong, Chunhua, Liu, Zhanxiang, Zhang, Yuhong
Format: Article
Language:English
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Summary:The first example of oxidant-free cobalt-catalyzed synthesis of five-membered spirocycles is reported from benzimidates and maleimides utilizing nitrobenzene as promoter. In contrast to previously known cobalt-catalyzed oxidative C–H functionalization reactions, this transformation occurs efficiently in the absence of oxidant and is accompanied by liberation of hydrogen. The spiro-lactams were readily achieved by the hydrolysis of as-prepared spirocyclic compounds. The Cp*Rh­(III) catalyst shows poor reactivity.
ISSN:1523-7060
1523-7052
DOI:10.1021/acs.orglett.7b02266