Metal-Free [2+2+1] Annulation of Alkynes, Nitriles, and Oxygen Atoms: Iodine(III)-Mediated Synthesis of Highly Substituted Oxazoles

The metal-free [2 + 2 +1] annulation of alkynes, nitriles, and O-atoms for the regioselective assembly of 2,4-disubstituted and 2,4,5-trisubstituted oxazole compounds has been achieved by the use of PhlO with TfOH or Tf2NH. The present reaction could be applied to a facile synthesis of an anti-inflammatory drug.