Abstract: α-Bromination of aliphatic ketones using 1,3-dibromo-5,5-dimethylhydantoin (DBDMH) in methanol at room temperature was described. α-Chlorination of aliphatic ketones, β-keto-esters and malonic ester using 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) and p-toluenesulfonic acid in acetonitrile at 25 ℃ was also reported. β-Keto-esters and dimethyl malonate give α-monochloroproducts in high yields (87%~96%).

Key words: α-bromination, aliphatic ketones, β-keto-esters and malonic ester, 3-dichloro-5, 5- dimethylhydantoin, α-chlorination, α-bromination, aliphatic ketones, β-keto-esters and malonic ester, 3-dichloro-5, 5- dimethylhydantoin