Synthesis of New Chiral Crown Ethers Containing Phosphine or Secondary Phosphine Oxide Units

The transition-metal complexes of phosphine and secondary phosphine oxide compounds can be used in various catalytic reactions. In this paper, the synthesis and characterization of eight new crown ethers containing trivalent phosphorus in their macroring are reported. These macrocycles are promising candidates as ligands for catalytic reactions.

Enantiodiscrimination Using a Chiral Crown Ether as a Chiral Solvating Agent Using NMR Spectroscopy

For enantiomer separation of a variety of chiral compounds, a number of chiral selectors have been developed and applied. Among these chiral selectors are chiral crown ethers, a class of synthetic polyether molecules that bind protonated chiral primary amines with high selectivity. This article focuses on enantiodiscrimination using (18-crown-6)-2,3,11,12-tetracarboxylic acid as a crown ether-type chiral solvating agent for nuclear magnetic resonance spectroscopic method in several chirotechnologies.