A one-step β-selective glycosylation of N-acetyl glucosamine and recombinant chitooligosaccharides

N-Acetyl glucosamine and chitooligosaccharides are selectively converted into β-glycosides without protection of the other hydroxyl groups by alkylation of the anomeric alkoxides in N,N-dimethylformamide containing lithium bromide. Addition of the lithium salt notably improves the stereoselectivity of the glycosylation of the monomer and the efficiency of the process with higher oligomers.