Asymmetric synthesis of $alpha$ -(heteroaryl)alkylamines and -amino acids via nucleophilic 1,2-addition of lithiated heterocycles to aldehyde SAMP-hydrazones

Abstract

The asymmetric synthesis of -(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 SmI2 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 -amino acids (ee = 90%{99%).