Solvent-free mechanochemical glycosylation in ball mill

• Solvent-free mechanochemical glycosylation of poorly nucleophilic alcohols is reported.
• Zinc and cadmium carbonates were found to be the best promoters.
• A pentenyl glycoside so prepared was converted into a β-hydroxy triazole derivative in the same pot.
• One-pot multi-step process in carbohydrate chemistry is possible in a ball mill.

Starting from acetobromosugars and an alcohol (alkyl/substituted alkyl/akenyl/alkynyl/glyceryl/cyclohexyl/steryl) various O-glycosides have been prepared mechanochemically under solvent-free conditions employing a planetary ball mill in the presence of metal carbonates (environmentally benign or otherwise) as promoters. The method was proven to be mild and efficient and applicable on preparative scale for the synthesis of various mono- and disaccharide glycosides. 4-Pentenyl glycoside so produced could, in four successive reactions in the same pot, be converted in high isolated yields into triazole-substituted pentyl glycoside that can find application in the area of medicinal chemistry.

Solvent-free mechanochemical glycosylation in the presence of metal carbonates as promoters has been optimized for application to reactions of poorly nucleophilic alcohol acceptors with glycosyl halides and is reported for the first time and on preparative scale. CdCO3 and ZnCO3 have been found to be the best promoters. A pentenyl glycoside thus prepared was converted into the corresponding β-hydroxy triazole derivative in three successive additional steps in the same pot.Figure optionsDownload as PowerPoint slide