A method includes combining first components including at least one of CF2═CF—CF2—OSO2Cl or CF2═CF—CF2—OSO2CF3, a polyfluorinated compound having at least one ketone or carboxylic acid halide, and fluoride ion to provide a compound comprising at least one perfluorinated allyl ether group. A method includes combining second components including B(OSO2Cl)3 and hexafluoropropylene to provide CF2═CF—CF2—OSO2Cl. Another method includes combining second components including M(OSO2CF3)3 and hexafluoropropylene at a temperature above 0° C. to provide CF2═CF—CF2—OSO2CF3, wherein M is Al or B. The compound CF2═CF—CF2—OSO2Cl is also provided.