Enantiodiscrimination of carboxylic acids using single enantiomer thioureas as chiral solvating agents

Abstract Structurally simple enantiopure thioureas were used as chiral solvating agent (CSA) for the rapid determination of enantiomeric purity of chiral carboxylic acids by 1H NMR spectroscopy in the presence of DMAP. The formation of diasteromeric complexes between the enantiopure thiourea and carboxylate-DMAPH+ ion pair gave rise to well-resolved 1H NMR signals of the enantiomers of carboxylic acids. Furthermore, thiourea S,S-1 was used to assign the absolute configuration of mandelic acid.