Pyranophane transannular diels-alder approach to (+)-chatancin: a biomimetic asymmetric total synthesis

J Org Chem. 2003 Dec 26;68(26):9983-7. doi: 10.1021/jo035193y.

Abstract

An asymmetric total synthesis of (+)-chatancin was achieved via a transannular Diels-Alder (TADA) reaction of an in situ generated macrocyclic pyranophane pseudobase. The presented route constitutes the second of two proposed biosynthetic pathways that involves a TADA reaction. It links this diterpene biogenetically to the cembranoids. A set of TADA selection rules that rationalize the formation of (+)-chatancin from a dynamic equilibrium of four 2-hydroxy-2H-pyrane bicycles and their 16 potential TADA transition states are also outlined. Beyond the TADA reaction, highlights of the synthetic work include the assembly of a chiral acyclic macrocyclization substrate from (S)-citronellol and an efficient macrocyclization via a beta-ketosulfoxyde/enone Michael addition.

MeSH terms

  • Biomimetics / methods
  • Cyclization
  • Diterpenes / chemical synthesis*
  • Diterpenes / chemistry
  • Furans / chemistry
  • Pyrans / chemistry*
  • Stereoisomerism

Substances

  • Diterpenes
  • Furans
  • Pyrans
  • chatancin