A synthesis of orthogonally protected L-threo-beta-hydroxyasparagine from L-aspartic acid is reported. Iodocyclization of 3-benzoylaminoaspartic acid provided an intermediate oxazoline dicarboxylate that was efficiently hydrolyzed to L-threo-beta-hydroxyaspartic acid. The synthetic route for conversion of the free beta-hydroxy-alpha-amino acid into the target compound is highly efficient and amenable to preparation various orthogonally protected asparagine derivatives, on a multiple gram scale.