Simple and efficient methods for selective preparation of alpha-mono or alpha,alpha-dichloro ketones and beta-ketoesters by using DCDMH

New processes that can selectively prepare alpha-mono or alpha,alpha-dichloro ketones and beta-ketoesters using 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) are reported. Using silica gel as the catalyst and methanol as the solvent and heating for 1 h under reflux, alpha-monochlorinated products were selectively obtained in 86-98% yield. However using a deep eutectic solvent (choline chloride: p-TsOH = 1:1) as the solvent and stirring for 45 min at room temperature, alpha,alpha-dichlorinated products were selectively obtained in 86-95% yield.