Abstract: Using N-(S)-a-or N-(R)-a-methylbenzyl-3-aminopropan-l-ol as the starting material, the diastereomers of 2-chloro-3-[(S)-a-or (R)-a-methylbenzyl] tetrahydro-2H-l, 3, 2- oxazaphosphorine 2-oxide were obtained in the ratio 80: 20. Their conversion via P- aziridines (14) into 2-chloroethylamino derivatives (15) and separation of the latter into diastereometrically pure forms allowed the further synthesis of enantiomers of ...