Formal Synthesis of (+)-Brefeldin A: Application of a Zinc-Mediated Ring Expansion Reaction
journal contributionposted on 08.06.2007, 00:00 by Weimin Lin, Charles K. Zercher
An efficient formal synthesis of (+)-brefeldin A was accomplished through a synthetic approach that relied upon three keys steps. The five-membered ring was generated in a stereocontrolled fashion through application of a tandem conjugate addition-intramolecular cyclization method developed by Toru. Ring-closing metathesis provided access to a twelve-membered β-keto lactone, which was ring-expanded to the α,β-unsaturated-γ-keto lactone through a zinc carbenoid-mediated reaction. Conversion of this lactone to (+)-brefeldin A has been reported previously.