Chemoenzymatic synthesis of (4S)- and (4R)-4-methyl-2-oxoglutaric acids, precursors of glutamic acid analogues

Alkylation of dimethyl 2,2-dimethoxyglutarate followed by enzymatic resolut ion afforded (4S)- and (4R)-4-methyl-2-oxoglutaric acid inn enantiomericall y pure form. The activity of glutamic oxalacetic transaminase towards these compounds has been measured. Their enzymatic transamination provides an ef ficient synthesis of (4S)- and (4R)-4-methyl-L-glutamic acids which are ver y useful for characterisation of glutamate receptors in the central nervous system.