2.2 Transfer Hydrogenation of Ketones to Alcohols

Abstract Transfer hydrogenation offers an alternative to hydrogenation using gaseous hydrogen, as well as a practical synthetic approach to enantiopure compounds. Alcohols, formic acid, and formate salts are often used as safe and nontoxic hydrogen sources in transition-metal catalyzed transfer hydrogenation systems. This chapter highlights effective transfer hydrogenation and asymmetric transfer hydrogenation of ketones catalyzed by transition-metal complexes. The reactions described in this section are classified according to the reducing agents employed and the type of ketone substrate.