New reactions of fluorinated 2,4-dioxoesters with aromatic aldehydes

4-Polyfluoroalkyl 2,4-dioxobutanoates react with aromatic aldehydes to give 4-aryl-2,6-dihydroxy-2,6-di (fluoroalkyl)-3,5-diethoxalyltetrahydropyrans 3a,b, whereas the reaction of 4-pentafluorobenzoyl 2,4-dioxobutanoate with benzaldehyde gives 5,6,7,8-tetrafluoro-1-phenyl-1H-furo[3,4-b]chromene-3,9-dione 4.