30. Stereoselective Synthesis of β-manno-Glycosides

Among the various types of O‑glycosides with biological relevance, the β‑glycoside of d‑mannose (β‑manno-glycoside) has been considered as one of the most challenging targets from a synthetic point of view. The majority of synthetic approaches to β‑manno-glycoside can be put into two categories (the direct glycosylation and the glycosylation‐inversion approaches). Additionally, a variety of intriguing approaches have been investigated with substantial success (alkylative glycosylation of 1,2‑stannylene acetal, reductive manipulation of orthoester, intramolecular aglycon delivery, and enzymatic glycosylation). In this chapter, progress in the conceptually demanding β‑mannosylation technology will be discussed, including current state of the art, with particular focus upon applications related to the synthesis of glycoprotein‐related oligosaccharides.