Highly Enantioselective Synthesis of Optically Active Ketones by Iridium-Catalyzed Asymmetric Hydrogenation

Close to perfect enantioselectivity (up to 99 % ee, see scheme) is found for the formation of α‐substituted ketones by the asymmetric hydrogenation of enones with an iridium–phosphinooxazoline catalyst. In an operationally simple process, both linear and cyclic substrates react well and afford the desired products in high yields. A wide variety of substituents are tolerated, thus making the method synthetically appealing.