Highly Selective Glycosidation Reactions Capitalizing on Phosphorus- Containing Leaving Groups

The rational design and development of stereocontrolled glycosidation reactions has been the subject of intensive investigations. Our interest in this context has been centered on the design of the leaving groups of glycosyl donors coupled with their activation without resorting to precious, explosive, or toxic heavy-metal salts as promoters. In an effort to capitalize on the phosphorus-containing leaving groups, we have recently devised new glycosyl donors incorporating diphenyl phosphate, diphenylphosphinimidate, N, N, N', N'-tetramethylphosphoroamidate, phosphorodiamidimidothioate, or diethyl phosphite as leaving groups, the glycosidations of which constitute mild and efficient methods for the highly stereocontrolled construction of 1, 2-trans-β-and 1, 2-cis-α-glycosidic linkages. In this paper, several notable features of the present glyosidation methods coupled with the mechanistic aspects are described.