A rhodium-catalyzed heterocycloaddition route to 5-fluoroalkyl substituted 1,3-oxazoles

In the presence of catalytic rhodium (II) acetate, ethyl 2-diazo-fluoroalkylacetoacetate, obtained from the reaction of ethyl fluoroalkylacetoacetate with perfluoroalkanesulfonyl azide or tosyl azide, reacted readily with nitriles to give a series of 5-fluoroalkyl substituted 1,3-oxazoles in fair to good yields.