Disclosed herein are phosphorus-containing actives, their use as actives for treating diseases, and a stereoselective process for preparing the same. Also disclosed herein are useful synthetic intermediates and processes for preparing the same. A process for preparing a composition comprising an enantiomerically- or a diastereomerically-enriched phosphorus-containing active, salt, or pharmaceutically acceptable salt thereof, of formula I is disclosed: 1 which comprises a) reacting a protected or unprotected Active with a base to form a salt of said active and then reacting said salt with an enantiomerically- or a diastereomerically enriched compound of formula II wherein Group is as defined herein, W is an aryl or -CCH2)nSC(O)C(CH3)m(CH2OH)3-m, where n is 2 or 3 and m is 0, 1, 2, or 3, and LG is a leaving group; b) optionally deprotecting the compound obtained in step a) and c) optionally subjecting the compound obtained in step a) or the compound obtained in step b) to chromatography, extraction, or crystallization to obtain the active.La présente invention concerne des agents actifs contenant du phosphore, leur utilisation en tant qu'agents actifs pour traiter des maladies, et un procédé stéréosélectif pour préparer ceux-ci. La présente invention concerne en outre des intermédiaires synthétiques utiles et des procédés pour préparer ceux-ci.