Di-<i>tert</i>-butylsilylene (DTBS)-Directed Stereoselective Glycosylations

Abstract

In carbohydrate chemistry, many useful stereoselective glycosylation methods have been developed that control the stereochemistry of the newly formed glycosylated product in chemical glycosylation. For example, in the past decade, unique stereoselective glycosylation methods have been reported that use glycosyl donors in which the ring is conformationally restricted by the di-tert-butylsilylene (DTBS) group as a cyclic silyl protecting group. To date, glycosyl donors with the DTBS group have been used to control the stereoselectivity of diverse chemical glycosylations for the formation of α-galactosides/galactosaminides, β-arabinofuranosides, α-sialosides, α-galactofuranosides, β-glucuronides, β-glucosides, β-mannosides, α-Kdo glycosides, and α-glucosides. Furthermore, the effect of ring-restriction for stereoselective glycosylations has provided new insights into the reaction mechanism of chemical glycosylation. This review provides a historical overview of stereoselective glycosylations using DTBS-tethered glycosyl donors and their application to the synthesis of biologically relevant carbohydrate molecules.