Automated Synthesis of C1-Functionalized Oligosaccharides

Automated glycan assembly (AGA) streamlines the synthesis of complex oligosaccharides. The reducing end of the oligosaccharide serves as an attachment site to the polymer support to liberate a free reducing end or an aminopentanol for ready conjugation to carrier proteins or surfaces. The facile installation of different aglycons on oligosaccharides has not been possible via AGA until now. Here, we describe a latent-active approach enabled by a traceless photolabile linker that allows for bidirectional AGA and ready introduction of various aglycons. Oligosaccharide thioglycosides, peptidoglycans, prototypical saponins, and click-chemistry-based conjugates are synthesized to illustrate the versatility of the method.