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oai:figshare.com:article/34034149 2026-09-30T17:08:17Z category_1 category_4 category_146 category_7 category_19 category_21 category_873 category_39 category_45 category_46 category_133 portal_63 item_type_6 month_year_09_2026

Modular Strategy for the Collective Total Synthesis of Pandanus amaryllifolius Alkaloids: Pandanusines A and B and Pandamarine Edouard Fauran (25144930) Jean-Valère Naubron (1433524) Laurent Commeiras (2492713) Biophysics Biochemistry Space Science Medicine Pharmacology Biotechnology Chemical Sciences not elsewhere classified Ecology Sociology Immunology Plant Biology construct diazaspirocyclic backbones )- catalyzed reaction pandanus amaryllifolius </ protecting group strategy complex alkaloid pandamarine readily accessible γ collective total synthesis (±)- pandanusine b total synthesis n </ (±)- pandanusine strategy enabled modular strategy versatile precursors unambiguously determined terminal alkynes synthetic potential subsequently transformed separated enantiomers results demonstrate rapid construction primary amines overall yield modular copper lactam frameworks iodoacrylic acids four steps five steps absolute configurations <i>Pandanus amaryllifolius</i> produces structurally unique alkaloids, including pandanusines A and B and pandamarine, featuring rare diazaspirocyclic γ-lactam frameworks. Herein, we report concise total syntheses of these three natural products based on a modular copper(I)-catalyzed reaction. Readily accessible γ-hydroxy-γ-lactams were prepared from iodoacrylic acids, terminal alkynes, and primary amines and subsequently transformed through <i>N</i>-acyliminium ion intermediates to construct diazaspirocyclic backbones. This strategy enabled the synthesis of (±)-pandanusine B in four steps (40% overall yield) and (±)-pandanusine A in five steps (26.5% overall yield) after optimization of the protecting group strategy. The methodology was further extended to the total synthesis of the more complex alkaloid pandamarine. These results demonstrate the synthetic potential of γ-hydroxy-γ-lactams as versatile precursors for the rapid construction of architecturally complex alkaloid scaffolds. Furthermore, the absolute configurations of both HPLC-separated enantiomers of pandanusine A and B were unambiguously determined through a combination of vibrational and electronic circular dichroism analyses and DFT and TD-DFT calculations. 2026-09-30T00:00:00Z Text Journal contribution 10.1021/acs.joc.6c01791.s002 https://figshare.com/articles/journal_contribution/Modular_Strategy_for_the_Collective_Total_Synthesis_of_Pandanus_amaryllifolius_Alkaloids_Pandanusines_A_and_B_and_Pandamarine/34034149 CC BY-NC 4.0