Development and application of chiral crown ethers as selectors for chiral separation in high-performance liquid chromatography and nuclear magnetic resonance spectroscopy

Chiral crown ethers have been widely used in the resolution of various chiral compounds containing a primary amino group. Covalently bonded chiral stationary phases derived from (18-crown-6)-2,3,11,12-tetracarboxylic acid (18-C-6-TA) were developed in our groups and utilized for the resolution for several types of analytes. By use of NMR spectroscopy, chiral discrimination studies were performed for α-amino acids and their esters using 18-C-6-TA. Here, advances in the development and application of chiral stationary phases and chiral solvating agents using 18-C-6-TA for enantiomer resolution are described in relationship to recent chiral recognition mechanism studies.