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Published on: June 10, 2021
Total Syntheses of Daphenylline, Daphnipaxianine A, and Himalenine D
Yu Chen1, Wenhao Zhang1, Lu Ren1
1State Key Laboratory of Bioorganic and Natural Products Chemistry, Collaborative Innovation Center of Chemistry for Life Sciences, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China.
Abstract:
We report the total syntheses of daphenylline (1), daphnipaxianine A (5), and himalenine D (6), three Daphniphyllum alkaloids from the calyciphylline A subfamily. A pentacyclic triketone was prepared by using atom-transfer radical cyclization and the Lu [3+2] cycloaddition as key steps. Inspired by the proposed biosynthetic relationship between 1 and another calyciphylline A type alkaloid, we developed a ring-expansion/aromatization/aldol cascade to construct the tetrasubstituted benzene moiety of 1. The versatile triketone intermediate was also elaborated into 5 and 6 through a C=C bond migration/aldol cyclization approach.
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