The Development of DNA-Compatible S-Glycosyl Transformations

In this study, we revealed two distinct S-glycosyl transformations in a DNA-encoded library (DEL)-compatible environment. The first approach involves 2-chloro-1,3-dimethylimidazolidinium chloride (DMC)-mediated S-glycosylation, which is facilitated by the coupling of unprotected sugar units with the thiol residue of the DNA-linked compounds. However, this methodology falls short of the requirement for DEL construction due to its limited substrate scope. We further investigated a photoinduced DNA-compatible S-glycosyl transformation through a radical process. In this alternative approach, allyl sugar sulfones serve as sugar donors and are conjugated to DNA-linked compounds upon irradiation with green light. Encouragingly, this on-DNA glycosyl chemistry demonstrated excellent compatibility with functional groups presented in both sugar units and peptides, affording the desired DNA-linked glycosyl derivatives with good to excellent conversions. This pioneering DNA-compatible S-glycosyl transformation represents a valuable tool, facilitating the preparation of glycosyl DELs and offering avenues for the exploration of sugar-incorporated delivery systems.