SYNTHESIS OF HOMOCHIRAL ALPHA-SUBSTITUTED ALANINE DERIVATIVES BY DIASTEREOCONTROLLED ALKYLATION OF (5R)-5-PHENYL-3-METHYL-3,4-DEHYDROMORPHOLINONES

Dehydromorpholinones, 1 a-d, have been prepared by direct condensation of (R)-phenylglycinol with alpha-ketoesters in refluxing trifluoroeth anol. Chemo- and diastereoselective alkylation of the imine moiety of la furnished trisubstituted morpholinones, 4, and subsequent cleavage of the cyclic template revealed homochiral alpha-substituted alanine d erivatives, 5.