2-(1-Phenylvinyl)benzoic acid as a highly active leaving group for metal-free glycosylation†

In the field of modern biochemistry and drug development, the acquisition of homogeneous sugar complexes is crucial for evaluating their biophysical activities. These sugar complexes are essential for understanding biomacromolecule functions and serve as potential vaccine candidates. The synthesis of sugar conjugates is a key step in achieving this goal, and the selection of sugar donors and control of glycosylation reaction outcomes are particularly important in this process. Our recent research indicates that glycosyl PVB donors exhibit self-stability, high reactivity, and excellent yields when activated by NIS/TMSOTf promoters. Notably, glycosyl PVB donors can achieve similar glycosylation effects with I₂ activation. These metal-free reaction conditions are broadly applicable to the synthesis of various O-glycosides, N-glycosides, and the carbohydrate drug PG545 (an anti-tumor agent).