Divergence en route to nonclassical annonaceous acetogenins. Synthesis of pyranicin and pyragonicin

J Org Chem. 2006 Mar 3;71(5):1879-91. doi: 10.1021/jo052233k.

Abstract

Syntheses of the nonclassical annonaceous acetogenins, pyranicin, and pyragonicin from common late-stage intermediates are presented. The construction of key elements relies on asymmetric HWE reactions, including the desymmetrization of a meso-dialdehyde and a parallel kinetic resolution of a racemic aldehyde. A stereoconvergent Pd-catalyzed substitution serves to install the C4 stereocenter in protected form with different orthogonal protective groups. A divergent strategy to form 1,4- and 1,6-diols, employing stereoselective Zn-mediated alkynylations, is used for completion of the core structures. Notably, the stereoselective coupling reaction toward pyragonicin proceeds with highly functionalized fragments. The methodology is further expanded by a divergent synthesis of all stereoisomers of the 2,3,6-trisubstituted tetrahydropyran subunit.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4-Butyrolactone / analogs & derivatives
  • 4-Butyrolactone / chemistry
  • Acetogenins
  • Catalysis
  • Cyclization
  • Fatty Alcohols / chemical synthesis*
  • Furans / chemical synthesis*
  • Lactones / chemical synthesis*
  • Platinum / chemistry
  • Pyrans / chemistry
  • Stereoisomerism

Substances

  • Acetogenins
  • Fatty Alcohols
  • Furans
  • Lactones
  • Pyrans
  • pyragonicin
  • pyranicin
  • Platinum
  • butenolide
  • 4-Butyrolactone