Abstract
One of the practical applications of sugar-based crown ethers involves their use as chiral catalysts in enantioselective phase transfer reactions. Chiral crown ethers incorporating various monosaccharide units in the macrocyclic structure are reviewed which may be efficient enantioselective catalysts in certain asymmetric reactions, such as Michael addition, epoxidation of α,β-enones and Darzens condensation.
Keywords: Chiral crown ethers, phase transfer catalysis, enantioselective synthesis, monosaccharide, Cram's macrocycles, Carbohydrates, chiral ethylene glycol, C-atom, heteroatoms, crown ring, asymmetric phase, non-racemic, inorganic salt, onium salts, chiral HPLC, 1H NMR spectroscopy, NaCN, toluene, L-xylose, D-xylose, deprotonation, Michael reaction, transition, solid-liquid phase reaction, N-substituents, lipophilicity, Glycine Esters, Michael Acceptors, Epoxidation, Molecular modeling, DFT, Darzens Condensation, trans-epoxyketones, trans isomer, Hydrogenation, CD-spectra