Intermolecular Addition of Glycosyl Halides to Alkenes Mediated by Visible Light

摘要

C-glycosides are an important class of bioactive compounds most notable for their resistance to metabolic processing and their prevalence in natural products. Perhaps the most identifiable methodology for their synthesis is the Bu3SnH-mediated radical addition of glycosyl bromides to activated alkenes. Since its discovery, several variations of this reaction have been reported, including the utilization of transition metalsor UV light to initiate the reaction. Our group recently developed a nickel-catalyzed reductive coupling of glycosyl bromides and alkenes, mechanistic studies on which suggested that the nickel catalyst was playing an electron-transfer (ET) role, which implied that other compounds that are known to facilitate ET processes might behave even better (for example, [Ru(bpy)3]~(2+); bpy = 2,2'-bipyridyl).