The syntheses of chlorinated 5-hydroxy-furanones with a mono-, di-, and trichloromethyl group at C-5 are described. The 5-chloromethyl hydroxyfuranones were obtained by chlorination of levulinic acid followed by triethylamine promoted elimination of hydrogen chloride. Hydrolyses of chlorinated 4-cyclopentene-1, 3-diones yielded 5-dichloromethyl hydroxyfuranones. The trichloromethyl group was incorporated to maleic anhydride ...