Tracking the leaving group in the remote activation of O -2-[(propan-2-yl)sulfinyl]benzyl (OPSB) glycoside

Glycosylation with sulfoxide-based glycosyl donors

Sulfoxides have emerged as pivotal constituents in modern carbohydrate chemistry. As anomeric leaving groups, sulfinyl moieties may occupy positions directly at the anomeric position or at a more remote site. This feature article is focused on the evolution and notable advancements of glycosyl sulfoxide donors in glycosylation reactions. Its objective is to elucidate the obstacles and prospects within this evolving research domain, with the aim of enhancing comprehension and progress in the field of carbohydrate chemistry.

Glycosylation of 2-(2-Propylsulfinyl)benzyl 1,2-Orthoester Glycosides Initiated by Sulfoxide Activation

We have developed a highly effective glycosylation method that involves the activation of 2-(2-propylsulfinyl)benzyl 1,2-orthoester glycosides using triflic anhydride (Tf2O). Our research indicates that half of the glycosyl donor is activated through Tf2O via an interrupted Pummerer reaction mechanism, while the remaining portion is activated by triflic acid (TfOH) generated in situ. As a result, as little as 0.5 equiv of Tf2O is adequate for activating the orthoester glycoside donors. This glycosylation procedure offers several benefits, such as high efficiency, wide applicability, and the utilization of a recyclable leaving group.

Recyclable Fluorous-Tag Assisted Two-Directional Oligosaccharide Synthesis Enabled by Interrupted Pummerer Reaction Mediated Glycosylation

Herein, we report a novel fluorous-tag assisted two-directional oligosaccharide assembly strategy, which combines the advantages of solution-phase synthesis and solid-phase synthesis. A well-designed fluorous-tag was decorated on the latent anomeric...

Total synthesis of tricolorin A via interrupted Pummerer reaction-mediated glycosylation and one-pot relay glycosylation

Tricolorin A, a bioactive resin glycoside, was synthesized stepwise or in one pot based on interrupted Pummerer reaction-mediated (IPRm) glycosylation. The stepwise synthesis adopted a [2 + 2] assembly sequence, and all of the glycosidic bonds were constructed efficiently by IPRm glycosylation. The one-pot synthesis employed our recently developed one-pot relay glycosylation strategy, in which two different glycosidic bonds were sequentially connected with only one equivalent of external activator.

Sequential activation of thioglycosides enables one-pot glycosylation

This review describes recent developments in relative reactivity value (RRV) controlled sequential glycosylation, pre-activation based iterative glycosylation, and sulfoxide activation initiated one-pot glycosylation.

Practical synthesis of active O-2-(2-propylsulfinyl)benzyl (OPSB) glycosides via a catalytic and metal free oxidation of latent O-2-(2-propylthiol)benzyl (OPTB) glycosides

A catalytic and metal free sulfoxidation of O-2-(2-propylthiol)benzyl (OPTB) glycosides to O-2-(2-propylsulfinyl)benzyl (OPSB) glycosides has been developed by introducing NOBF₄ as catalyst, oxygen as terminal oxidant and TBAB as additive. Wide variety of OPTB glycosides were efficiently oxidized without observation of over oxidation. The allowance of large scale synthesis, easy operation and purification highlighted its practical application in construction of complex oligosaccharides and glycoconjugates employing interrupted Pummerer reaction mediated glycosylation strategy.

Diversified synthesis and α-selective glycosylation of 3-amino-2,3,6-trideoxy sugars

Quick access to various unnatural 3-amino-2,3,6-trideoxy sugars was achieved by sequential functionalization of a glycal intermediate. This strategy and the further glycosylation method allowed the efficient late-stage modification of bioactive natural products and drugs.