C1-symmetric aza-crown ethers as chiral shift agents for amines and amino acid derivatives

Abstract

Reported herein is our recent research progress in the development of macrocyclic chiral recognition studies. Highly enantiopure C1-symmetric aza-crown ethers, which were prepared previously by our lab from catalytic enantioselective symmetry-breaking C (sp3)-H bond transformation of readily available and inexpensive aza-crown ethers, were useful 1H NMR chiral shift reagents to resolve racemic amines and amino acid derivatives, providing an easy and rapid NMR assay of enantiomeric purity of chiral compounds, especially chromophore-devoid ones that are not detected and quantified by colorimetric method.