Photoinduced Ruthenium-Catalyzed meta-C-H Glycosylation

C-H functionalization has surfaced as a powerful tool in molecular synthesis. meta-Selective arene C-H activations typically rely on rather costly palladium or rhodium catalysts, elaborate template auxiliaries, or elevated temperatures, and meta-glycosylations are scarce. In contrast, we herein report on a visible-light-induced ruthenium-catalyzed meta-C-H glycosylation that utilizes a stable ruthenium-(II) catalyst under exceedingly mild conditions at room temperature. This strategy is operative without an exogenous photocatalyst. The versatile ruthenium-(II) catalyst featured high meta- and anomeric α-selectivity, employing readily accessible glycosyl bromides.