The asymmetric synthesis of α-(heteroaryl)alkylamines was accomplished by employing a diastereoselective nucleophilic 1,2-addition of lithiated aromatic heterocycles to aldehyde SAMP-hydrazones, followed by BH3·THF or SmI 2 promoted removal of the chiral auxiliary. The CBz or benzoyl-protected amines were obtained in good yields (40%–78%) and excellent enantiomeric excesses (ee = 88%–99%). The methodology can be applied to the synthesis of highly enantioenriched α-amino acids (ee = 90%–99%). |
