Indium(Ⅲ)-catalyzed Synthesis Of Glycosides

Complex carbohydrates are involved in a wide range of biological processes such as cell-cell recognition,fertilization,proliferation of cells,viral and bacterial infection,and tumor cell metastasis.Furthermore,carbohydrates are capable of inducing a protective antibody response.The increased appreciation of the role of carbohydrates in the biological and pharmaceutical sciences has resulted in a revival of interest in carbohydrate chemistry.A major obstacle to advances in glycobiology and glycomedicine is the lack of pure and structurally well-defined carbohydrates and glycoconjugates.These compounds are often found in low concentrations and in microheterogeneous forms,greatly complicating their isolation and characterization.In many cases,well-defined oligosaccharides can only be obtained by chemical or enzymatic synthesis.Based on the progress in chemical preparation of glycosides,in our study the new methods of propagating S-glycosides,Se-glycosides and O-glycosides under the catalysis of indium were developed.The reaction conditions are mild and do not require strict exclusion of air and moisture.The operational simplicity of the method should allow experimentalists with a limited synthetic background to construct glycosidic linkages.