Abstract
Securinega alkaloids constitute a structurally diverse class of natural products with intriguing architectures and biological activities. Herein, we report the discovery of four new Securinega alkaloids, flueggeacosines D–F and securingine J, from Flueggea suffruticosa. Flueggeacosines D and E possess dimeric frameworks incorporating a benzoquinolizidine motif derived from allosecurinine backbone. A concise synthetic strategy combining TBADT-catalyzed radical hydroacylation and Mo(CO)6-mediated reductive rearrangement enables efficient access to these complex alkaloids. Our synthetic approach also realizes a synthesis-based natural product anticipation predicting and confirming the existence of flueggeacosine F and securingine J in F. suffruticosa. Furthermore, oxidative rearrangements of flueggeacosine A furnish flueggeacosines D and F, supporting a plausible biosynthetic linkage. These findings establish a unified route to oxidized dimeric Securinega alkaloids and demonstrate the synergy of synthesis and biosynthetic reasoning in natural product discovery.
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Acknowledgements
This work is dedicated to Prof. Eun Lee (1946–2025) in memory of his contribution to organic synthesis. The authors thank Dr. Dongwook Kim (IBS) for his assistance with single-crystal X-ray diffraction analysis of compounds 16 and 21. The authors also thank Mr. Taewan Kim (KAIST) for providing the raw ECD data of allosecurinine (11). Financial support was provided by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (RS-2026-25474353, S.H.) and by the InnoCORE program of the Ministry of Science and ICT (N10250153, C.L.). We appreciate the support by KAIST Cross-Generation Collaborative Lab Project (S.H.). This work was also supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT; grant numbers RS-2019-NR040057 and RS-2021-NR059240, K.H.K.) and the Korea Environment Industry & Technology Institute (KEITI) through a project to make multi-ministerial national biological research resources more advanced, funded by the Korea Ministry of Environment (MOE; 2021003420003, K.H.K.). This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (RS-2024-00440614, K.H.K.).
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Lee, C., Chae, S.H., Kang, G. et al. Discovery and synthesis of flueggeacosines D–F and securingine J. Nat Commun (2026). https://doi.org/10.1038/s41467-026-72871-1
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DOI: https://doi.org/10.1038/s41467-026-72871-1
