Stereoselective synthesis of allo-threonine and β-2H-allo-threonine from threonine

Article abstract of DOI:10.1016/S0040-4039(00)79241-0

Both D- and L-allo-threonine can be synthesized in good yield from D- and L-threonine respectively, by protection of the amine with Fmoc and the carboxyl with a cyclic ortho ester, followed by oxidation of the side chain to a ketone, and diastereoselective reduction to the allo isomer. Deprotection gives the amino acid in 40% overall yield. The β-hydrogen can be labelled during reduction.