Chiral tertiary amines have been examined as enantioselective decarboxylation–reprotonation reagents for the synthesis of α-amino acids via α-aminomalonates. N-Acetyl pipecolic acid ethyl ester, as a modelcompound, was obtained in good yield and 52% enantiomeric excess using a quinidine derived base.
Enantioenriched pipecolic esters were prepared in good yields in the decarboxylation, at room temperature, of N-protected piperidinohemimalonates catalyzed by cinchona alkaloids. Enantiomeric excesses as high as 72% were obtained when using 9-epi-cinchonine and the N-benzoyl substituted piperidinohemimalonate. A detailed study of the different reaction parameters revealed that the selectivity of this