A novel and practical synthesis of (R)-serine-gd that is stoichiometric in its use of deuterium is described. Isopropyl (R, S)-2-phenyl-2-oxaoline-4-carboxylate is metalated, deuteriated, resolved, and hydrolyzed to provide the optically pure (> 99.8%) unnatural amino acid with> 98% isotopic purity. Fluorination of the primary hydroxyl with SF4 produces (S)-3- fluoroalanine-2-d (Fludalanine).
