Chemical O‐Glycosylations: An Overview

Abstract

The development of glycobiology relies on the sources of particular oligosaccharides in their purest forms. As the isolation of the oligosaccharide structures from natural sources is not a reliable option for providing samples with homogeneity, chemical means become pertinent. The growing demand for diverse oligosaccharide structures has prompted the advancement of chemical strategies to stitch sugar molecules with precise stereo‐ and regioselectivity through the formation of glycosidic bonds. This Review will focus on the key developments towards chemical O‐glycosylations in the current century. Synthesis of novel glycosyl donors and acceptors and their unique activation for successful glycosylation are discussed. This Review concludes with a summary of recent developments and comments on future prospects.

Enantio‐ and Diastereoselective, Lewis Base Catalyzed, Cascade Sulfenoacetalization of Alkenyl Aldehydes

“…The preferential formation of the α‐anomer may be a manifestation of the kinetic anomeric effect resulting in the placement of the HFIP group in the axial position, but experimental confirmation was not possible. In addition, the enhanced diastereomeric ratio of the benzannulated product could be attributed to stabilization of the cationic oxocarbenium intermediate by the adjacent aryl substituent …”

Machine‐Driven Enzymatic Oligosaccharide Synthesis by Using a Peptide Synthesizer

“…Synthetic preparation by either chemical or enzymatic glycosylation is the only way to obtain amounts of homogeneous oligosaccharides sufficient for research applications. Chemical glycosylation can produce structurally defined glycans with diverse natural and unnatural structures, [6] while enzymatic glycosylation can produce both simple and complicated glycans with high regio- and stereo-specificity under mild reaction conditions. [7] Regardless, both chemical and enzymatic methods require skilled researchers to perform the operation, which is a time-consuming and labor-intensive process.…”

Synthesis of Oxaphosphinane‐Based Pseudodisaccharides

“…[2] In the modern therapeutic arsenal, glycosidic or pseudoglycosidic molecules are of great interest for the treatment of diverse pathologies. [9,10] In this paper, we present the synthesis of pseudodisaccharides based on an oxaphosphinane core. In addition to this approach, Bertozzi et al have highlighted the potential of more complex saccharidic oligomers to be used in glycanbased therapies.…”

“…The synthesis of inhibitors of these enzymes may lead to the development of potential therapeutic agents. [9,10] In this paper, we present the synthesis of pseudodisaccharides based on an oxaphosphinane core. The main goal was to develop heteroatom analogues of carbohydrates to provide the closest analogy with the anomeric carbon without its drawbacks.…”