Synthesis of highly substituted oxazoles through iodine(III)-mediated reactions of ketones with nitriles.

In the presence of trifluoromethanesulfonic acid (TfOH) or bis(trifluoromethane-sulfonyl)imide (Tf₂NH), iodosobenzene (PhI=O) efficiently promoted the reactions of dicarbonyl compounds as well as monocarbonyl compounds with nitriles to give 2,4-disubstituted and 2,4,5-trisubstituted oxazole in a single step under the mild conditions.