Design, development, mechanistic elucidation, and rational optimization of a tandem Ireland Claisen/Cope rearrangement reaction for rapid access to the (iso)cyclocitrinol core

J Am Chem Soc. 2014 Jul 16;136(28):9878-81. doi: 10.1021/ja505131v. Epub 2014 Jun 30.

Abstract

An approach to the synthesis of the (iso)cyclocitrinol core structure is described. The key step is a tandem Ireland Claisen/Cope rearrangement sequence, wherein the Ireland Claisen rearrangement effects ring contraction to a strained 10-membered ring, and that strain in turn drives the Cope rearrangement under unusually mild thermal conditions. A major side product was identified as resulting from an unexpected and remarkably facile [1,3]-sigmatropic rearrangement, and a tactic to disfavor the [1,3] pathway and increase the efficiency of the tandem reaction was rationally devised.

Publication types

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

MeSH terms

  • Lactones / chemical synthesis
  • Lactones / chemistry
  • Models, Molecular
  • Molecular Conformation
  • Stereoisomerism
  • Terpenes / chemical synthesis*

Substances

  • Lactones
  • Terpenes
  • cyclocitrinol