To probe the reaction mechanism, underlying the rearrangementofoft-used trichloroacetimidate glycosyl donors into the correspondinganomeric trichloroacetamides, we have used a combination of C-13-... Show moreTo probe the reaction mechanism, underlying the rearrangementofoft-used trichloroacetimidate glycosyl donors into the correspondinganomeric trichloroacetamides, we have used a combination of C-13- and N-15-labeled glycosyl trichloroacetimidate donorsin a series of crossover experiments. These unambiguously show thattrichloroacetamides are formed via an intermolecular aglycon transfermechanism. This insight enables the design of more effective glycosylationprotocols, preventing the formation of dead-end side products. Show less
Hengst, J.M.A. van; Hellemons, R.J.C.; Remmerswaal, W.A.; Vrande, K.N.A. van de; Hansen, T.; Vorm, S. van der; ... ; Codee, J.D.C. 2023
The reactivity of the acceptor alcohol can have a tremendous influence on the outcome of a glycosylation reaction, both in terms of yield and stereoselectivity. Through a systematic survey of 67... Show moreThe reactivity of the acceptor alcohol can have a tremendous influence on the outcome of a glycosylation reaction, both in terms of yield and stereoselectivity. Through a systematic survey of 67 acceptor alcohols in glycosylation reactions with two glucosyl donors we here reveal how the reactivity of a carbohydrate acceptor depends on its configuration and substitution pattern. The study shows how the functional groups flanking the acceptor alcohol influence the reactivity of the alcohol and show that both the nature and relative orientation play an essential role. The empiric acceptor reactivity guidelines revealed here will aid in the rational optimization of glycosylation reactions and be an important tool in the assembly of oligosaccharides. Show less
