Chiral Phosphoric Acid Catalyzed Enantioselective Transfer Hydrogenation of ortho‐Hydroxybenzophenone NH Ketimines and Applications

Unprotected synthesis: The first enantioselective chiral phosphoric acid catalyzed transfer hydrogenation of unprotected ortho-hydroxybenzophenone NH imines by using a Hantzsch ester as the hydrogen source afforded the corresponding chiral N,O-unprotected ortho-hydroxydiarylmethylamines in high yields with excellent enantioselectivities (see scheme).