5-Perfluoroalkylpyrazoles 6, 5-perfluoroalkylisoxazoles 11, and 4-perfluoroacylisoxazoles 13 are obtained in high chemical yields and complete site and regioselectivity through the reaction of beta-perfluoroalkyl-beta-dicarbonyls 2 with hydrazonyl halides 1 and halooximes 8 in the presence of bases.