3-Polyfluoroalkyl-substituted E-cinnamic acids: easy access via Perkin reaction

3-Polyfluoroalkyl-(E)-cinnamic acids being very useful building blocks were obtained by a simple and convenient one-step procedure. The Perkin type reaction of fluoroacyl-substituted arenes gives the titled compounds in good yields and excellent stereoselectivity independent on the electronic nature of substituents in the aromatic ring. In the case of fluoroalkyl–alkylketones only O-acylation occures under the same conditions.