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Updated: Apr 18, 2026

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Asymmetric total synthesis of (-)-lundurine B and determination of its absolute stereochemistry
Masaya Nakajima1, Shigeru Arai, Atsushi Nishida
1Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba 260-8675 (Japan).
Abstract:
A total synthesis of the Kopsia tenuis alkaloid (-)-lundurine B has been achieved. A quaternary chiral carbon has been created by an asymmetric deprotonation using a symmetric spiro cyclohexanone intermediate with a chiral lithium amide. The hexacyclic skeleton was sequentially constructed through metal-mediated reactions. The absolute stereochemistry of intermediate 5 has been unambiguously established by X-ray crystallographic analysis. This is the first description of the absolute stereochemistry of Kopsia tenuis alkaloids based on chemical synthesis.
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