Efficient synthesis of 3-hydroxyprolines and 3-hydroxyprolinols from sugars

trans-3-Hydroxy-l-proline 1, trans-3-hydroxy-l-prolinol 2, cis-3-hydroxy-d-proline 3, and cis-3-hydroxy-d-prolinol 4 have been prepared in enantiomerically pure form with chirospecific manner. Key intermediates, 2-amino-3-hydroxy-4-pentenoate 9 and 17, were obtained from d-glucono-δ-lactone and l-gulonic acid γ-lactone via a simultaneous dealkoxyhalogenation.