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

Authors: DIETER ENDERS, GIUSEPPE DEL SIGNORE, GERHARD RAABE

Abstract: The asymmetric synthesis of \alpha-(heteroaryl)alkylamines was accomplished by employing a diastereoselective nucleophilic 1,2-addition of lithiated aromatic heterocycles to aldehyde SAMP-hydrazones, followed by BH_3 . 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 \alpha-amino acids (ee = 90\%--99\%).

Keywords: Amines, asymmetric synthesis, SAMP-hydrazone, nucleophilic addition, amino acids

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