Resumen
A number of chiral macrocyclic compounds have been prepared that contain a monosaccharide-derived sub-unit. These sugar-based crown ethers were used as chiral phase transfer catalysts in a few asymmetric reactions. A few of them proved to be effective catalysts in Michael additions, a Darzens condensation and an epoxidation of a,ß-enones. It was found that the type of the monosaccharide, the substituents on the sugar unit and on the nitrogen atom of the macroring have a significant influence on both the yield and the enantioselectivity.