Chemoenzymatic Synthesis of a New Class of MacrocyclicOligosaccharides

摘要

A novel and highly efficient chemoenzymatic method has been developed for the preparation of structurallydefined macrocyclic oligosaccharides of varied sizes. This method involves chemical or chemoenzymaticsynthesis of oligosaccharides containing a galactose at the nonreducing end and a propargyl group at thereducing end as sialyltransferase acceptors. Introducing an azido-containing sialic acid to the nonreducingend of the galactosides through a sialyltransferase-catalyzed enzymatic reaction followed by copper(I)-catalyzed Huisgen' s 1,3-dipolar cycloaddition of alkyne and azide provides size-defined macrocycliccarbohydrates. The produced negatively charged macrocycles have high solubility in water and interactwith hydrophobic small molecules in a size-dependent manner.