Acyl chloride/DABCO-promoted acetal migration of 1,2:4,5-di-O-isopropylidene-d-fructopyranose

An unprecedented acetal migration was observed when 1,2:4,5-di-O-isopropylidene-d-fructose was treated with various acyl chlorides and 1,4-diaza-bicyclo[2.2.2]octane (DABCO). 2,3:4,5-Di-O-isopropylidene-d-fructose derivatives were isolated as the only product in high to quantitative yields. The acylium cations generated in situ were speculated as the electrophilic species to initiate the migration process.

Figure optionsDownload as PowerPoint slide