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Updated: Jan 1, 2026

Enzymatic Cascade Reactions for the Synthesis of Chiral Amino Alcohols from L-lysine
Published on: February 16, 2018
Demethylative Lactonization Provides a Shortcut to High-Yielding Syntheses of Lamellarins
Robin Klintworth1, Charles B de Koning1, Joseph P Michael1
1Molecular Sciences Institute, School of Chemistry , University of the Witwatersrand , Wits 2050 , Johannesburg , South Africa.
Abstract:
Modular gram-scale syntheses of the trimethyl ethers of lamellarins G (6) and D (7) were achieved from readily accessible precursors in the highest overall yields reported to date (6, six steps, 82%; 7, seven steps, 86%). A novel demethylative lactonization between an aryl methyl ether and a neighboring carboxylic acid was developed for creating the chromenone unit of the targets to avoid the need for additional protection and deprotection steps. The central pyrrole core was constructed in a late-stage [4 + 1] condensation between ethyl bromoacetate and an enaminone possessing the remaining components of the lamellarin skeleton. Exhaustive demethylation of both permethyl ethers 6 and 7 gave the polyphenolic natural lamellarins A4 (3) and H (5), respectively.
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