An enantioselective total synthesis of (+)- and (-)-saudin. Determination of the absolute configuration

J Am Chem Soc. 2002 Jan 16;124(2):190-1. doi: 10.1021/ja017194i.

Abstract

A short efficient enantioselective synthesis of both (+)- and (-)-saudin, a naturally occurring hypoglycemic diterpene, is described. This synthesis establishes the absolute configuration of natural (-)-saudin for the first time. The key steps include the enantioselective construction of a dimethyl Hagemann's ester by an asymmetric Michael reaction and establishment of the key 1,3 disposed quaternary centers by means of a novel Ti(IV) promoted Claisen rearrangement. The assembly of the polycyclic ketal skeleton was likely under kinetic control proceeding via formation of the C1oxygen-C7 bond through an oxonium ion intermediate in the final stage.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Diterpenes / chemical synthesis*
  • Diterpenes / chemistry
  • Hypoglycemic Agents / chemical synthesis
  • Hypoglycemic Agents / chemistry
  • Molecular Conformation
  • Plant Extracts / chemical synthesis
  • Plant Extracts / chemistry
  • Stereoisomerism

Substances

  • Diterpenes
  • Hypoglycemic Agents
  • Plant Extracts
  • saudin