A ruthenium(II)/phosphine catalysis system enabled versatile meta-arene C−H glycosylation by σ-activation. Thus, easily accessible glycosyl bromide donors furnished 1,2-trans C-aryl glycosides via robust ruthenium(II) catalysis under exceedingly mild conditions.
The prevalence of C-aryl glycosides in biologically active natural products and approved drugs has long motivated the development of efficient strategies for their selective synthesis. Cross-couplings have been frequently used, but largely relied on palladium catalyst with prefunctionalized substrates, while ruthenium-catalyzed C-aryl glycoside preparation has thus far proven elusive. Herein, we disclose a versatile ruthenium(II)-catalyzed meta-C−H glycosylation to access meta-C-aryl glycosides from readily available glycosyl halide donors. The robustness of the ruthenium catalysis was reflected by mild reaction conditions, outstanding levels of anomeric selectivity and exclusive meta-site-selectivity.Zum Volltext