A Visible‐Light‐Driven O ‐Glycosylation with Selenoglycosides Mediated by Chalcogen Bonding to Umemoto's Reagent

The activation of chalcogenoglycosides for O-glycosylation typically involves strong electrophiles requiring low temperature. Herein, we demonstrate that visible-light irradiation of selenoglycosides in the presence of Umemoto's reagent results in often high-yielding O-glycosylation. We provide evidence that this process is mediated by a novel mode of reactivity, specifically photoinduced electron transfer within a chalcogen-bonded complex.