Asymmetric Hydrogenation of a-Amino Esters into Optically Active beta-Amino Alcohols through Dynamic Kinetic Resolution Catalyzed by Ruthenabicyclic Complexes

Racemic alpha-substituted alpha-amino esters were hydrogenated into enantioenriched beta-amino alcohols through dynamic kinetic resolution with chiral ruthenabicyclic complexes. The reaction was carried out with a substrate/catalyst molar ratio of 200-1000 under 15 atm of H-2 at 25 degrees C to afford a variety of beta-substituted beta-aminoethanols in up to 96% ee (24 examples). The mechanistic studies including deuteration experiments suggested that the reaction proceeds with 1,2-hydride migration of the a-amino acetalate intermediate into the alpha-hydroxy imine followed by the continuous reduction of the imino compound, affording the amino alcohol product.

Automated summary

Racemic alpha-substituted alpha-amino esters were hydrogenated into enantioenriched beta-amino alcohols through dynamic kinetic resolution with chiral ruthenabicyclic complexes. The reaction proceeded with 1,2-hydride migration of the a-amino acetalate intermediate into the alpha-hydroxy imine followed by the continuous reduction of the imino compound, affording the amino alcohol product.