Direct Dehydrative Glycosylation Catalyzed by Diphenylammonium Triflate.

Mei-Yuan Hsu,Chia-Hui Wu,Su-Ching Lin,Cheng-Chung Wang,Mei-Huei Lin,Sarah Lam

doi:10.3390/molecules25051103

Abstract

Methods for direct dehydrative glycosylations of carbohydrate hemiacetals catalyzed by diphenylammonium triflate under microwave irradiation are described. Both armed and disarmed glycosyl-C1-hemiacetal donors were efficiently glycosylated in moderate to excellent yields without the need for any drying agents and stoichiometric additives. This method has been successfully applied to a solid-phase glycosylation.

Highlights

Glycosylation is one of the most important reactions in oligosaccharide synthesis [1].Though monosaccharides in hemiacetal form are commercially available or prepared, use of them as glycosyl donors often requires prior elaboration of the anomeric hydroxyl to a good leaving group [2,3,4,5,6,7]
The glycosylation could be promoted by conventional heating, microwave heating in general gave cleaner and more reliable results
The workup procedure merely involved quenching with trimethylamine, followed by removal of solvent, and the desired glycosylation product was readily isolated by chromatography

Summary

Introduction

Glycosylation is one of the most important reactions in oligosaccharide synthesis [1].Though monosaccharides in hemiacetal form are commercially available or prepared, use of them as glycosyl donors often requires prior elaboration of the anomeric hydroxyl to a good leaving group [2,3,4,5,6,7]. We disclose a glycosylation reaction driven by water exclusion, which encompasses a microwave-assisted method for direct dehydrative glycosylations of both armed and disarmed saccharides by using diphenylammonium triflate (DPAT) as an efficient and green catalyst. The dehydrative glycosylation did not proceed without the catalyst under similar conditions (Table 1, entry 1).

Results

Conclusion