Total synthesis of the originally proposed and revised structures of palmerolide A and isomers thereof

J Am Chem Soc. 2008 Mar 19;130(11):3633-44. doi: 10.1021/ja710485n. Epub 2008 Feb 26.

Abstract

Palmerolide A is a recently disclosed marine natural product possessing striking biological properties, including potent and selective activity against the melanoma cancer cell line UACC-62. The total syntheses of five palmerolide A stereoisomers, including the originally proposed (1) and the revised [ent-(19-epi-20-epi-1)] structures, have been accomplished. The highly convergent and flexible strategy developed for these syntheses involved the construction of key building blocks 2, 19-epi-2, 20-epi-2, ent-2, 3, ent-3, 4, and ent-4, and their assembly and elaboration to the target compounds. For the union of the building blocks, the Stille coupling reaction, Yamaguchi esterification, Horner-Wadsworth-Emmons olefination, and ring-closing metathesis reaction were employed, the latter being crucial for the stereoselective formation of the macrocycle of the palmerolide structure. The Horner-Wadsworth-Emmons olefination and the Yamaguchi lactonization were also investigated and found successful as a means to construct the palmerolide macrocycle. The syntheses were completed by attachment of the enamide moiety through a copper-catalyzed coupling process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Macrolides / chemical synthesis*
  • Macrolides / chemistry*
  • Molecular Conformation
  • Stereoisomerism

Substances

  • Macrolides
  • palmerolide A