Chiral Amino Acids: A Versatile Tool in the Synthesis of Pharmaceuticals and Fine Chemicals

Abstract

Methods of preparing enantiomerically pure amino acids especially focusing on amino-acylase-based resolution of D,L-acetylamino-acid precursors, synthesis of D-amino acids using a hydantoinase system, and the cofactor-dependent enzymatic reductive amination of α-keto acids to L-amino acids are described. Examples are given for bulk actives, based on L- and D-amino acids and peptides. L- and D-Tle (= L-/D-2-amino-3,3-dimethylbutanoic acid) are important molecules for synthesizing drugs and a great variety of chiral auxiliaries. A new chromatographic separation of bulky side-chain amino acids in a preparative scale is described, giving both enantiomers in >99% ee.