The insertion of fluorinated 1,3-dicarbonyl compounds to benzyne resulted in regioselective formation of various fluorinated 1,5-dicarbonyl compounds which are not readily available by other methods. Products include 2-trifluoroacetyl- and 2-(perfluoroalkanoyl)phenylacetic estres, 2-fluoro-2-phenylacetic esters, 1-aryl-2-(2-trifluoroacetylphenyl)ethan-1-ones and other derivatives.