- Synthetic routes to various quaternary -nitro -methyl carboxylic acid esters from simpler nitroalkanes and nitroalkane derivatives are described. These quaternary -amino acid precursors can be kinetically resolved by using -chymotrypsin. It was found that partial hydrolysis of these nitro -methyl esters and recovery of the unhydrolyzed ester proceeds preferentially by hydrolysis of the D enantiomer. Reduction of the -nitro group thus then affords highly enantiomerically enriched L--methyl -amino acids. 1988, American Chemical Society. All rights reserved.