Method for stereoselectively synthesizing alpha-oxoglycoside from 3-O-quinaldine glycal donor

A method for stereoselectively synthesizing alpha-oxoglycoside based on a 3-O-quinaldine acid ester glycal donor comprises the following steps: taking 3-O-quinaldine acid ester glucose glycal as a sugar donor, adding a catalyst, a ligand, triethylamine, a sugar receptor and an organic solvent, stirring at 100-120 DEG C, monitoring the reaction process by TLC (Thin Layer Chromatography), terminating the reaction after the reaction is carried out for 20-24 hours, and filtering to obtain the alpha-oxoglycoside. And the alpha-2, 3-unsaturated oxyglycoside can be obtained. According to the technical scheme, in a beta-configuration product preferentially generated during glycosylation reaction, original beta-glucosidic bonds are broken and regenerated in an alpha configuration under the action of high temperature and the palladium catalyst, the alpha-2, 3-unsaturated oxyglycoside with thermodynamic stability is obtained, and the method has wide substrate applicability and is suitable for industrial production. And