Efficient Construction of (±)- epi -Costunolide through a Chromium(II)-Mediated Nozaki-Hiyama-Kishi Reaction

Abstract

(±)- epi -Costunolide has been synthesized through a seven-step procedure starting from (E, E)-farnesol. The key step includes an intramolecular allylation of an aldehyde through a chromium(II)-mediated Nozaki-Hiyama-Kishi reaction, in which more than one equivalent of CrCl 2has been recognized as the most effective reagent to promote the conversion. An anti-inflammatory screen showed that epi -costunolide is a moderate inhibitor of B lymphocyte proliferation.