Improved synthesis of (R)-glycine-d-15N

Previously, we have synthesized the title glycine to permit assignment of the prochiral α-protons of glycine residues in the NMR study of the protein FKBP. A key, and low yielding step in this synthesis occurs in the ruthenium tetraoxide mediated degradation of N-t-Boc-p-methoxybenzyl amine to N-t-Boc-glycine. Efforts to improve this key step by exploring different substrates and N-protecting groups were successful to render this synthesis amenable for the large scale production of (R)-glycine-d-15N.