Photochemical Approach to Glycan Synthesis

Carbohydrates (glycans, oligo- and poly-saccharides) are the most abundant biopolymers in nature. They are assembled from a monosaccharide building blocks that have multiple alcohol functional groups but vary in their structural features. This amazing variety accounts for the many biological roles of carbohydrates but makes their synthesis a very complex task because it requires the functionalization of a specific alcohol moiety in a sea of very similar groups. Because the synthesis and isolation of carbohydrates is very difficult, understanding their biological function is still an immense challenge. Automated Glycan Assembly (AGA) is a strategy that aims to facilitate the procurement of oligosaccharides, therefore to expedite the understanding of the roles of carbohydrates. This platform rely on automated solid phase protocols and differs in many aspects from traditional step-wise oligosaccharide synthesis that is performed in solution. The development of the automated approach requires a reevaluation of traditional approaches. This motivates us to explore new synthetic and technological methods in order to make the automated synthesis reliable, reproducible but still remain easy enough to use. One of the most attractive research direction rely on the combination of photochemical and automated methods. We will describe the recent development in this field, highlight few of the remaining challenges and present new strategies that aimed to further aid the procurement of well-defined oligosaccharides.