Scalable Total Syntheses of Some Natural and Unnatural Lamellarins: Application of a One-Pot Domino Process for Regioselective Access to the Central 1,2,4-Trisubstituted Pyrrole Core
Short and scalable total syntheses of lamellarinGtrimethylether, lamellarin D trimethylether, lamellarin H, lamellarin η, dihydrolamellarin η, and lamellarin U have been realized in four to six linear steps with an overall yield of ≤22%. Highlights of the synthesis include single-step access to the central 1,2,4-trisubstituted pyrrole core in a highly regioselective manner via a one-pot [3+2]
Demethylative Lactonization Provides a Shortcut to High-Yielding Syntheses of Lamellarins
作者:Robin Klintworth、Charles B. de Koning、Joseph P. Michael
DOI:10.1021/acs.joc.9b02983
日期:2020.1.17
Modular gram-scale syntheses of the trimethylethers of lamellarinsG (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