Synthesis of orthogonally protected (2S, 4R)- and (2S, 4S)-4-hydroxyornithine was reported featuring an asymmetric alkylation of N-(diphenylmethylene)glycine tert-butyl ester (6) by (5S)-N-benzyloxycarbonyl-5-iodomethyl oxazolidine (7). Double stereoselection was examined using chiral ammonium salts as phase transfer catalysts and a substrate-directed chiral induction is documented.