Abstract The reaction of alcohols with tetra- o-acetylbromoglucose in the presence of silver nitrate (Koenigs-Knorr reaction) is re-examined. The influence of several crown ethers, cryptands and supported ligands are studied. With t-BuOH, the reaction leads to a mixture of sugar nitrate and glycoside. We discuss the yield and the selectivity obtained with free and immobilized ligands. Supported macrocycles which assist the reaction increase the glycoside formation. The polymer effect on the selectivity is explained in terms of steric hindrance.