An efficient [2 + 2 + 1] synthesis of 2,5-disubstituted oxazoles via gold-catalyzed intermolecular alkyne oxidation

J Am Chem Soc. 2011 Jun 8;133(22):8482-5. doi: 10.1021/ja2029188. Epub 2011 May 12.

Abstract

The first efficient intermolecular reaction of gold carbene intermediates generated via gold-catalyzed alkyne oxidation has been realized using nitriles as both the reacting partner and the reaction solvent, offering a generally efficient synthesis of 2,5-disubstituted oxazoles with broad substrate scope. The overall reaction is a [2 + 2 + 1] annulation of a terminal alkyne, a nitrile, and an oxygen atom from an oxidant. The reaction conditions are exceptionally mild, and a range of functional groups are easily tolerated. With complex and/or expensive nitriles, only 3 equiv could be sufficient to achieve serviceable yields in the absence of any solvent and using only 1 mol % BrettPhosAuNTf(2) as the catalyst.

Publication types

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

MeSH terms

  • Alkynes / chemistry*
  • Catalysis
  • Gold / chemistry*
  • Molecular Structure
  • Oxazoles / chemical synthesis*
  • Oxazoles / chemistry
  • Oxidation-Reduction

Substances

  • Alkynes
  • Oxazoles
  • Gold