ASYMMETRIC DIASTEREOSELECTIVE CONJUGATE ADDITIONS OF LITHIUM AMIDES TO CHIRAL NAPHTHYLOXAZOLINES LEADING TO NOVEL BETA-AMINO ACIDS

The functionalization of the naphthalene ring system by a direct amination-alkylation reaction of chiral nonracemic naphthyloxazolines is described. Chiral 1-naphthyl- and 2-naphthyloxazoline were treated with a variety of lithium amides followed by several different electrophilic quenches. The solvent and additives were varied in. order to achieve optimum conditions. The combination of HMPA and THF at -78 degrees C gave the best yield with excellent stereoselectivity. The present methodology provides a stereospecific synthesis of novel, nonracemic, rigid beta-amino acids after hydrolytic removal of the chiral oxazoline.