Chloroform Is <i>Not</i> Solvent but Activator for Cobalt Complex Catalyst of Enantioselective Borohydride Reduction

Abstract

Abstract For the enantioselective borohydride reduction of carbonyl compounds catalyzed by the optically active ketoiminatocobalt complexes, chloroform has been employed as a unique solvent for achieving a high enantioselectivity, whereas it was found that a catalytic amount of chloroform effectively activated the present catalytic system to convert various ketones into the corresponding reduced product with a high ee in the THF solvent.