Stereospecific synthesis of (2S,4R)-[5,5,5-2H3]leucine

The first stereospecific chemical synthesis of a sample of the amino acid (2S)-leucine labelled in one of the diastereotopic methyl groups has been achieved using (2S)-pyroglutamic acid as a chiral template. This has been used to develop a method for assigning resonances to the diastereotopic methyl groups of the leucine residues in the 1H NMR spectra of proteins.