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.

Automated summary

The prevalence of C-aryl glycosides in biologically active natural products and approved drugs has motivated the development of efficient synthesis strategies. Palladium catalysts with prefunctionalized substrates have been commonly used, while ruthenium-catalyzed C-aryl glycoside synthesis has been challenging. In this study, a versatile ruthenium(II)-catalyzed meta-C-H glycosylation method was disclosed, allowing for the synthesis of meta-C-aryl glycosides from readily available glycosyl halide donors. The ruthenium catalysis exhibited mild reaction conditions, exceptional levels of anomeric selectivity, and exclusive meta-site-selectivity.