Enzymatic Asymmetric Synthesis of α-Amino Acids. Enantioselective Cleavage of 4-Substituted Oxazolin-5-ones and Thiazolin-5-ones

Article abstract of DOI:10.1021/jo00064a010

A general enzymatic asymmetric synthesis of L-α-amino acids has been developed.This method entails the use of the Pseudomonas cepacia lipase (P-30) to catalyze the enantioselective methanolysis of a variety of 4-substituted 2-phenyloxazolin-5-one derivatives in a nonpolar organic solvent to furnish optically active N-benzoyl-L-α-amino acid methyl esters (ee = 66-98 percent), which in turn is subjected to a protease-catalyzed kinetic resolution yielding enantiomerically pure N-benzoyl-L-α-amino acids.This synergistic coupling of two enzymes allows the ready preparation of L-α-amino acids of high enantiopurity in yields greater than 50 percent, an inherent advantage over conventional resolution procedures.Two proteases were found to catalyze the enantioselective hydrolysis of a variety of 4-substituted 2-phenylthiazolin-5-one derivatives to give N-(thiobenzoyl)-L-α-amino acids of high optical purity.