Remote C−H Glycosylation by Ruthenium(II) Catalysis: Modular Assembly of meta‐C‐Aryl Glycosides

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.