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Total Synthesis of Chaxalactin B, a Rare 22‐Membered Macrolactone

Year: 2026

Type: article

Abstract: Chaxalactin B is a rare 22‐membered antibacterial macrolactone isolated from the extremophilic bacterium Streptomyces leeuwenhoekii C34 T collected in the Atacama Desert. Its highly functionalized carbon skeleton, featuring a challenging ( Z / E )‐diene, an all‐ E triene, and four contiguous stereogenic centers, makes it an attractive and challenging synthetic target. We report herein the first total synthesis of chaxalactin B, completed in 23 steps for the longest linear sequence. The synthesis relies on a convergent strategy involving the assembly of two main fragments: C1–C9 and C10–C25. Key features of this strategy include a highly diastereoselective Marshall propargylation to establish the C12–C13 stereocenters, efficient fragment assembly through cross‐coupling reactions, and a late‐stage Shiina macrolactonization to close the 22‐membered macrolactone.

Source: ChemistryEurope

DOI: 10.1002/ceur.70373