A three-component reaction of azole or azine N-oxides, 1,1-difluorostyrenes and amines gives amides of α-aryl-α-heteroarylacetic or propionic acids. The key step is 1,3-dipolar cycloaddition between N-oxide and difluorostyrene leading to the acyl fluoride intermediate, which has been identified and characterized by NMR spectroscopy. The whole process is an example of selective functionalization of C–H bonds in both 5- and 6-membered heterocyclic systems.