The application of the intermediate 2-methyl-glyco-[2,1-d]-2-oxazolines for glycoside synthesis

The synthesis of 2-acylamino-2-deoxysugars 1,2-trans-glycosides is described via the oxazolinium salt generated from an O,N-acetylated 1,2-cis-glycosyl halide of 2-amino-2-deoxysugar under the conditions of halide-anion catalysis. This salt was then interacted with alcohol to form the corresponding 1,2-trans-glycoside. A method for removing the generated hydrogen chloride is described. The conditions of this synthesis allow glycosides with acid-labile functional groups to be obtained. Suppression of the anomerisation of 1,2-trans-glycosides was achieved by the introduction of N,N′-dicyclohexyl urea into the reaction medium.