Asymmetric synthesis of β-heterocycle substituted l-α-amino acids

Abstract

A new efficient method of asymmetric synthesis of β-heterocycle substituted l-α-amino acids through the addition of 3-amino-1,2,4-thiodiazole and 5-mercapto-1,2,4-triazoles, containing various substituents at the 3 and 4 positions, to the CC bond of dehydroalanine in the Ni(II) complex of its Schiff base with ( S)-2- N-( N ′-benzylprolyl)aminobenzophenone has been elaborated upon. Under thermodynamic control, the stereoselectivity of the nucleophilic addition exceeded 94%. After acidic decomposition of the reaction mixtures, the corresponding β-heterocycle substituted α-amino acids with high enantiomeric purity (ee > 98.5%) were isolated.