Simple and efficient preparation of (R)- and (S)-enantiomers of α-carbon deuterium-labelled α-amino acids

Article abstract of DOI:10.1002/(SICI)1099-1344(200004)43:5<449::AID-JLCR331>3.0.CO;2-0

A procedure for the synthesis of (R)- and (S)-enantiomers of α-carbon deuterium-labelled α-amino acids, exemplified for (R)- and (S)-[2-²H₁]-Leu is described. Starting from the respective (S)- or (R)-enantiomer or from the racemic mixture of an α-amino acid the selective proton exchange at the α-carbon is carried out by racemization via a Schiff base in monodeuterated acetic acid as solvent which serves as deuterium source. After N-protection the racemic mixture is liquid chromatographically separated into the individual (R)- and (S)-enantiomers on preparative scale employing a chiral anion exchanger based on carbamoylated quinine as chiral selector. After deprotection the enantiomerically pure products can be obtained in good yields.