Koenigs‐Knorr Reaction

The Koenigs–Knorr reaction is the formation of O ‐glycosides from acetylated glycosyl halides and alcohols or phenols in the presence of a silver or mercury salt those functions as both promoter and halophile. This reaction has been extensively modified by means of using different promoters, different solvents of low polarity, and various desiccants to remove the generated water. The study finds that in modified conditions, this reaction usually gives only β‐ O ‐glycosides, except for certain conditions that use mercury salts as promoters. When carbohydrate itself is applied as an aglycone, the primary OH is considerably more reactive than the secondary OH. Besides this several other modifications have been applied for this reaction. This reaction is useful in the preparation of O ‐glycosides.