Synthesis of γ-pyrone precursors by condensation of acetyl ketene dithioacetals with ethyl polyfluorocarboxylates and diethyl oxalate

 β-Dicarbonyl compounds with the ketene dithioacetyl fragment were obtained by condensation of acetyl ketene dithioacetals with ethyl polyfluorocarboxylates and diethyl oxalate in the presence of NaH in Et2O at room temperature in 65–94% yields. These compounds can be used for the synthesis of 6-polyfluoroalkyl(ethoxycarbonyl)-2-methylsulfanyl-4-pyrones.