Chemoselectively Functionalized Ketoesters by Halogenative C–C Bond Cleavage of Cyclic Diketones

Haloketoesters are synthetic intermediates in various cyclization reactions that facilitate the production of biologically active compounds. Nonetheless, the selective synthesis of dihaloketoesters and trihaloketoesters, which are expected to be highly versatile, presents significant challenges. In this study, we designed a new synthetic approach that selectively and efficiently produces haloketoesters through the halogenative C–C bond cleavage and ring-opening reactions of cyclic 1,3-diketones. This convenient method enables the direct synthesis of di- and trichloro-functionalized ketoesters from 1,3-cyclohexadiones under mild conditions. Na2HPO4, employed as a buffer salt, proved to be effective in facilitating the alcoholytic ring-opening reaction of 2,2-dichloro-1,3-cyclohexadiones, which were generated as synthetic intermediates.