Formation of β -Lactones by[2+2] Cycloaddition of Dichloroketene with Unreactive Carbonyl Compounds

We report a modified process that dichloroketene generated in situ from trichloroacetyl chloride and Zn powder reacts with unreactivate carbonyl groups to afford dichloro-β-lactones in moderate to good yields. Subse-quently, monochloro-β-lactones, β-lactones and β-hydroxy ester are obtained by dechlorination under different reac-tion conditions.