Chemo-enzymatic deracemization methods for the preparation of enantiopure non-natural α-amino acids

The complete transformation of a racemate into one single enantiomer is defined as a deracemization. In amino acid chemistry, chemo-enzymatic deracemization is possible due to the ease of racemization of α-amino acids and the numerous enantioselective enzymatic systems operating on this class of compounds. Deracemization by dynamic kinetic resolution is a process in which the enantioselective catalyst is coupled with a second one promoting racemization of the reagent but not of the product. Deracemization by stereo-inversion is a convergent process in which the transformed isomer is finally converted into its enantiomer. These transformations can be applied for the preparation of enantiomerically pure α-amino acids of non-natural configuration or of l-α-amino acid of non-natural structure.