Expedient Synthesis of Alphitolic Acid and Its Naturally Occurring 2- O-Ester Derivatives

J Nat Prod. 2019 Apr 26;82(4):895-902. doi: 10.1021/acs.jnatprod.8b00986. Epub 2019 Feb 15.

Abstract

The expedient synthesis of alphitolic acid (1) as well as its natural C-3-epimer and 2- O-ester derivatives was accomplished in a few steps from the readily commercially available betulin (9). A Rubottom oxidation delivered an α-hydroxy group in a stereo- and chemoselective manner. The diastereoselective reduction of the α-hydroxy ketone was key to accessing the 1,2-diol moiety of this class of natural products. Our concise and stereoselective synthetic protocol allowed the gram-scale synthesis of these natural products, which will facilitate future biological evaluations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biological Products / chemical synthesis*
  • Biological Products / chemistry
  • Esters / chemistry
  • Molecular Structure
  • Oxidation-Reduction
  • Spectrum Analysis / methods
  • Stereoisomerism
  • Triterpenes / chemical synthesis*
  • Triterpenes / chemistry

Substances

  • Biological Products
  • Esters
  • Triterpenes
  • alphitolic acid