Asymmetric Synthesis of α-Chloro-α-halo Ketones by Decarboxylative Chlorination of α-Halo-β-ketocarboxylic Acids

Chiral alpha-chloro-alpha-fluoro ketones were synthesized by enantio-selective decarboxylative chlorination of alpha-chloro-beta-ketocarboxylic acids in the presence of a chiral amine catalyst. The reaction yielded the corresponding alpha-chloro-alpha-fluoro ketones with moderate-to-high enantioselectivity (up to 90% ee). The method was also applied to the synthesis of alpha-bromo-alpha-chloro ketones with 90% ee.