Palladium-Catalyzed Asymmetric Hydrogenation of N-Hydroxy-α-imino Phosphonates Using Bronsted Acid as Activator: The First Catalytic Enantioselective Approach to Chiral N-Hydroxy-α-amino Phosphonates

The enantioselective synthesis of ring-substituted [N-(hydroxy)amino](phenyl)methylphosphonic esters via asymmetric hydrogenation of the corresponding N-hydroxy-a-imino phosphonates with up to 90% ee was developed using catalytic amounts of palladium(II) acetate and (R)-BINAP in 2,2,2-trifluoroethanol with a Bronsted acid as an activator.