An α-selective, visible light photocatalytic glycosylation of alcohols with selenoglycosides

Exceptionally mild procedures for the visible light photocatalytic activation of selenoglycoside donors in the presence of alcohol acceptors have been developed. This process is demonstrated with both 1-phenylselenyl-2,3,4,6-tetra-O-benzyl glucoside (1) and 1-phenylselenyl-2,3,4,6-tetra-O-benzyl galactoside (2). Catalysis is effected with both metal (Ru(bpy)3) and organocatalysts (diphenyldiselenide). Reactions afford, in all cases, primarily the α-anomers with selectivities that vary with solvent. This represents the first example of a visible light-promoted O-glycosylation.

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► We developed a visible light photocatalytic O-glycosylation.
► Catalysis is effected with both Ru(bpy)3 and diphenyldiselenide.
► Glycosylation is α-selective with benzyl-protected selenoglycoside donors.
► α-Selectivity increases with the use of dichloromethane instead of acetonitrile.