Synthesis And Stereoselective Glycosylation Of 3,5-Cis-3-Aminodeoxysugars

3,5-cis-3-amino-2,3,6-trideoxypyranoses(3,5-cis-3-amino sugars)are a kind of rare sugars which exist in some natural products and drug molecules with important biological activities.Among these bioactive molecules,3,5-cis-3-amino sugars are usually linked to aglycones via O-glycosidic bond or C-glycosidic bond.The existence and structure of 3,5-cis-3-amino sugars play important roles in the biological activities of the parent compounds.But its natural content is scarce and separation is difficult.Therefore,the development of new approaches for its chemical synthesis and glycosylation method is of great significance for the study of its structure-activity relationship and the discovery of new 3-amino sugar drugs.In this strategy,the key 3,5-cis-3-amino sugars was obtained by the selective reduction of α and β unsaturated imine structure unit of sulfonyliminosene,avoiding the differential isomerization of C-4 site.Furthermore,six natural 3,5-cis-3-amino sugars methyl glycoside derivatives,L-daunosamiαne,L-rhodosaminide,L-acosaminide,D-daunosaminide,D-acosaminide,D-angolosaminide,were synthesized by functionalization of the double bond and the sulfamate portion of olefin,which solved the problem that the former method could not achieve in the synthesis 3,5-cis-3-amino sugars.On the basis of the research mentioned above,a stereoselective glucosylation method of 3,5-cis-3-amino sugars activated by Lewis acid was developed in this strategy.By using this method,the α-O-glycosidic bond and the β-C-glycosidic bond of 3,5-cis-3-amino sugars were successfully constructed.Among them,the method for construction of α-O-glycosidic bond is widely applicable to various primary and secondary alcohol glycosyl acceptor.β-C-Glycosylation mainly applied to phenol receptor,and it occurs in the ortho position of phenol hydroxyl group.For the receptor of aromatics containing methoxy,it occurs in the para position of methoxy group.These methods lay a foundation for the synthesis and modification of 3,5-cis-3-amino sugars.