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Updated: Jun 14, 2025
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Selenium dioxide promoted selenylation/cyclization of leucosceptrane sesterterpenoids
Hao Geng1, Ran Fu1,2, Ting-Ting Zhou1
1Key Laboratory of Phytochemistry and Natural Medicines, and Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, P. R. China. zhengyu@mail.kib.ac.cn.
Abstract:
A novel selenium dioxide promoted selenylation/cyclization of leucosceptrane sesterterpenoids was reported. Two types of leucosceptrane derivatives with different valence states of selenium atoms (Se2+ and Se4+) were obtained. The mechanisms of these two processes were proposed, and the selenium-containing derivates may serve as intermediates of Riley oxidation that could be trapped with appropriate substrates. Immunosuppressive activity screening revealed that 10 and 11 had obvious inhibitory effects on IFN-γ production, with IC50 values of 5.29 and 17.60 μM, respectively, which were more active than their precursor leucosceptroid A.
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