One of the most popular one-pot glycosylation strategies is orthogonal one-pot synthesis, which was mainly based on thioglycosides. Despite its successful application, shortcomings of thioglycosides including aglycon transfers, interference of departing species and unpleasant odor restrict its application scope. Herein, we report a new and efficient orthogonal one-pot synthesis of oligosaccahrides based on glycosyl ortho-alkynylbenzoate, which solves the issues of thioglycoside-based orthogonal one-pot synthesis. Over a dozen of oligosaccharides have been efficiently synthesized by this method.

The synthesis of long, branched, and complex carbohydrate sequences remains a challenging task in chemical synthesis. Reported here is an efficient and modular one‐pot synthesis of a nona‐decasaccharide and shorter sequences from Psidium guajava polysaccharides, which have the potent α‐glucosidase inhibitory activity. The synthetic strategy features: 1) several one‐pot glycosylation reactions on the basis of N‐phenyltrifluoroacetimidate (PTFAI) and Yu glycosylation to streamline the chemical synthesis of oligosaccharides, 2) the successful and efficient assembly sequences (first O3′, second O5′, final O2′) toward the challenging 2,3,5‐branched Araf motif, 3) the stereoselective 1,2‐cis‐glucosylation by reagent control, and 4) the convergent [6+6+7] one‐pot coupling reaction for the final assembly of the target nona‐decasaccharide. This orthogonal one‐pot glycosylation strategy can streamline the chemical synthesis of long, branched, and complicated carbohydrate chains.

The synthesis of long,b ranched, and complex carbohydrate sequences remains achallenging task in chemical synthesis.R eported here is an efficient and modular one-pot synthesis of anona-decasaccharide and shorter sequences from Psidium guajava polysaccharides,w hich have the potent aglucosidase inhibitory activity.The synthetic strategy features: 1) several one-pot glycosylation reactions on the basis of Nphenyltrifluoroacetimidate (PTFAI) and Yu glycosylation to streamline the chemical synthesis of oligosaccharides,2 )the successful and efficient assembly sequences (first O3',s econd O5',f inal O2')t owardt he challenging 2,3,5-branched Araf motif,3 )the stereoselective 1,2-cis-glucosylation by reagent control, and 4) the convergent [6+ +6+ +7] one-pot coupling reaction for the final assembly of the target nona-decasaccharide.This orthogonal one-pot glycosylation strategy can streamline the chemical synthesis of long,branched, and complicated carbohydrate chains.