Comparative study of different chiral ligands for dynamic kinetic resolution of amino acids

Abstract

Dynamic kinetic resolution (DKR) of unprotected amino acids (AAs), via intermediate formation of Ni(II) complexes, is currently a leading methodology for preparation of natural and tailor-made AAs in enantiomerically pure form. In this work, we conduct a comparative case study of synthetic performance of four different ligands in DKR of six AAs representing aryl-, benzyl-, alkyl-, and long alkyl-type derivatives. The results of this study allow for rational selection of ligand/AA type to develop a practical procedure for preparation of target enantiomerically pure AAs.

Keywords: Schiff bases; Tailor-Made Amino Acids™; asymmetric synthesis; dynamic kinetic resolution; square-planar Ni(II) complexes.