Reduction of (3S)-N,N-dibenzylamino-2-ketophosphonates 9a-d derived from L-amino acids was carried out with catecholborane at -20 oC to afford the (3S)-N,N-dibenzylamino-(2R)-hydroxy-phosphonates syn-10a-d, whereas the reduction of (3S)-N-benzylamino-2- ketophosphonates 13a-d with Zn(BH4)2 at -78 oC yield (3S)-N-benzylamino-( 2S)-hydroxyphosphonates anti-14a-d. The reduction in both cases was in good chemical yields and with high diastereoselectivity. The hydrolysis and hydrogenolysis of 10a-d and 14a-d afford the (3S)-amino-(2R)-hydroxyphosphonic acids 6 and (3S)-amino-(2S)- hydroxyphosphonic acids 7, respectively, which are analogues of phosphostatine.