The novel macrocyclic compounds as chiral solvating agents for determination of enantiomeric excess of carboxylic acids

Abstract

The novel macrocyclic compounds 1– 8 and acyclic compound 9 were designed and synthesized. 1H NMR studies demonstrated that 1 and 2 were the best chiral solvating agents, and are effective for the determination of the enantiomeric excess of a wide range of α-chiral carboxylic acids. Large non-equivalent chemical shifts (up to 411.2 Hz) can be achieved in the presence of 1 and 2. Quantitative analyses of a series of mandelic acids with different enantiomeric purities demonstrate that 1 and 2 are excellent chiral solvating agents for carboxylic acids.