Strategies toward protecting group-free glycosylation through selective activation of the anomeric center

Abstract

Glycosylation is an immensely important biological process and one that is highly controlled and very efficient in nature. However, in a chemical laboratory the process is much more challenging and usually requires the extensive use of protecting groups to squelch reactivity at undesired reactive moieties. Nonetheless, by taking advantage of the differential reactivity of the anomeric center, a selective activation at this position is possible. As a result, protecting group-free strategies to effect glycosylations are available thanks to the tremendous efforts of many research groups. In this review, we showcase the methods available for the selective activation of the anomeric center on the glycosyl donor and the mechanisms by which the glycosylation reactions take place to illustrate the power these techniques.

Rapid phenolic O-glycosylation of small molecules and complex unprotected peptides in aqueous solvent

“…6,7,8,9,10 While methods for the glycosylation of organic compounds are numerous, glycosylation methods typically require protection of glycosyl donors and acceptors. 11,12,13 The most common exceptions generally involve the application of glycosyl transferases in the enzymatic context. 14,15,16,17 The optimization of glycosylation methodology for reactions conducted in organic solvents has made applications on highly polar compounds such as native oligopeptides rare.…”

O‐Galactosylation of Diphenolic Compounds Using Boc Activation: A Convenient Chemical Synthesis

“…For example, in the central nervous system (CNS), the administration of flavonoids glycosides with secondary metabolites may activate GABA A receptors to mediate sedative effects. [6] Many strategies have been followed to deliver the potential drugs to their respective targets in the process of drug development [7,8] and one of the strategies is to synthesize the corresponding O-glycosides in the case of phenolic compounds. In the present work, we aim to develop a synthetic route for the O-glycosylation of diphenolic compounds using affordable promotors to achieve good yields.…”

Glycosylation on Unprotected or Partially Protected Acceptors

“…During the last 30 years, numerous procedures to avoid or decrease protecting group manipulations have been developed for the synthesis of a single oligosaccharide or an oligosaccharide library,, such as glycosylation on unprotected or partially protected acceptors, and random glycosylation on unprotected acceptors. Thiem et al published reviews on random glycosylation in 2008, and glycosylation on unprotected acceptors in 2014.…”