Enantioseparation of nonproteinogenic amino acids.

The enantioseparation of structurally related N-protected beta-/gamma-amino acids, beta-/gamma-amino amides, and beta-/gamma-amino nitriles by using six different commercially available chiral stationary phases (CSPs) is reported. The synthetic key step to introduce stereochemical asymmetry into all compounds is an enzymatic kinetic resolution of the racemic nitriles to the respective amino amides and/or amino acids, depending on the class of enzyme (nitrile hydratase or nitrilase) applied. The separation efficiencies of all CSPs with regard to functional groups as well as structural variations of the amino acid derivatives depicted in Fig. 1 are discussed.