Iridium/Monodentate Phosphoramidite Catalyzed Asymmetric Hydrogenation ofN-Aryl Imines

Asymmetric hydrogenation of N-aryl acetophenone imines using iridium/PipPhos leads to very high enantioselectivities up to >99% depending on the presence of electron-donating substituents in the 2-, 3-, and 5-position of the aryl ring. If the substituent is 2-methoxy, the resultant secondary amines are easily oxidatively deprotected using trichloroisocyanuric acid to give the primary amines in good yield with full retention of enantioselectivity.