Cyclopropenium Cation Promoted Dehydrative Glycosylations Using 2-Deoxy- and 2,6-Dideoxy-Sugar Donors

Dehydrative glycosylation reactions using 2-deoxy- and 2,6-dideoxy-sugar donors promoted by a combination of 3,3-dichloro-1,2-diphenylcyclopropene and tetrabutylammonium iodide (TBAI) are described. The reactions are a-selective and proceed under mild conditions at room temperature without the need for special dehydrating agents. The reaction is shown to be effective with a number of glycosyl acceptors, including those possessing acid and base sensitive functionality.