Stereocontrolled synthesis of all four stereoisomers of fully protected 2-amino-3-hydroxypentanoic acid from imines derived from D-glyceraldehyde

N-Benzylimines derived from conveniently protected (R)-glyceraldehyde underwent diastereoselective phenylmagnesium bromide addition to afford the corresponding aminodiols, whose absolute configuration at the newly formed stereogenic carbon depends on the O-protecting group. These compounds can be easily transformed into optically pure N-tert-butoxycarbonyl-1-phenyl-2,3-epoxy-1-propylamines, which are key intermediates in the synthesis of 2-tert-butoxycarbonylamino-3-acetyloxypentanoates of erythro and threo configuration.We thank DGES (PB97-0998) for financial support o f this research. We are also grateful to de D G I C Y T for a pre-doctoral fellowship to R. B.Peer reviewe