Asymmetric synthesis of anti-ß-amino-α-hydroxy esters via dynamic kinetic resolution of ß-amino-α-keto esters.

ABSTRACT

A method for the asymmetric synthesis of enantioenriched anti-α-hydroxy-ß-amino acid derivatives by enantioconvergent reduction of the corresponding racemic α-keto esters is presented. The requisite α-keto esters are prepared via Mannich addition of ethyl diazoacetate to imines followed by oxidation of the diazo group with Oxone. Implementation of a recently developed dynamic kinetic resolution of ß-substituted-α-keto esters via Ru(II)-catalyzed asymmetric transfer hydrogenation provides the title motif in routinely high diastereo- and enantioselectivity.