Advances on Photo-Promoted Glycosylation Reactions

Abstract

Carbohydrates, along with proteins and nucleic acids are known as basic life substances, which not only are the energy source and structure material, but also play an extremely important role in many biochemical processes, such as molecules recognition, information transformation in cells, interactions in immune response, differentiation and apoptosis of cells, etc. Compared to proteins and nucleic acids, the synthesis of oligosaccharides in chemical or enzymatic ways is more difficult, due to their diversified and complicated structures. Recently photo especially visible light promoted organic synthesis has become one of the fastest growing fields in organic chemistry attributed to its environmental friendliness, easy availability and low cost. This chemistry has also been applied to the photo-mediated glycosylation reactions by using various light sources (ultraviolet, visible light), photosensitizers (or photocatalysts), and additives (oxidants, reductants etc.), which provides milder and more effective ways for oligosaccharide assembly. To help chemists understand this field, we briefly reviewed recent advances and potential applications of photo-mediated glycosylation reactions according to their types (e.g. light sources, photosensitizers). In this review, we also detailly described the mechanisms and highlighted the advantages and limitations of these reactions. In addition, the further prospects of this area are proposed.

Visible Light-Promoted Amide Bond Formation via One-Pot Nitrone in Situ Formation/Rearrangement Cascade

“…Chemical reactions initiated using visible light as a green energy source have had a profound effect on the creation of unique reaction manifolds in organic synthesis that were previously difficult or unavailable to realize using traditional thermal approaches. [32][33][34][35][36][37][38][39][40][41] Pioneering work by Jurberg and Davies 42 revealed that aryldiazoacetates undergo photolysis efficiently to give reactive carbene singlet species under visible light. Due to the zwitterionic nature of the photogenerated singlet carbene, various nucleophilic atoms readily trap the electrophilic singlet carbene intermediate.…”