A Concise Synthesis of Oligosaccharides Derived From Lipoarabinomannan (LAM) with Glycosyl Donors Having a Nonparticipating Group at C2

Mycobacteria infection resulting in tuberculosis (TB) is one of the top ten leading causes of death over the world, and lipoarabinomannan (LAM) has been confirmed to play significant roles in this process. In this study, a convenient synthetic approach has been developed for the synthesis of oligosaccharides derived from LAM starting with commercially available substrates and reagents. The key steps for stereoselective construction of glycosidic bonds by acceptors glycosylated with donors without neighboring participating group were achieved. It's noteworthy that enzymatic hydrolysis was applied to prepare mannose building blocks and one step of birch reaction was used to deprotect acetyl and benzyl groups as well as reduce the azide group, which can avoid multiple chemical procedures. Finally, five oligosaccharides with terminal amino group at the anomeric substituent were furnished which could be used for conjugation with proteins as potential vaccines against TB.