Ligand Effect in Alkali-Metal-Catalyzed Transfer Hydrogenation of Ketones.

This work unveils the reactivity patterns, as well as ligand and additive effect on alkali-metal-base-catalyzed transfer hydrogenation of ketones. Crucially to this reactivity is the presence of a Lewis acid (alkali cation), as opposed to a simple base effect. With aryl ketones, the observed reactivity order is Na >Li >K , whereas for aliphatic substrates it follows the expected Lewis acidity, Li >Na >K .