First Syntheses of (−)-Tauranin and Antibiotic (−)-BE-40644 Based on Lipase-Catalyzed Optical Resolution of Albicanol

Abstract

First syntheses of sesquiterpene quinones (−)-tauranin and (−)-BE-40644 which exhibited strong cytotoxicity against several cancer cell lines, were achieved from (8aS)-albicanol obtained by enzymatic optical resolution. By comparison of the sign of specific rotation between synthetic (12bS)-BE-40644 and natural (−)-BE-40644, the absolute configurations of natural (−)-BE-40644 were determined to be 4aS, 6aS, 12aR, 12bS.