Stereoselective C-Aryl and C-Vinyl Glycosylation via Iron-Catalyzed Reductive Coupling.

The development of efficient and highly diastereoselective methods for the synthesis of C-aryl glycosides remains an important objective in carbohydrate and medicinal chemistry. Here, we report an iron-catalyzed reductive cross-electrophile coupling of glycosyl chlorides with aryl iodides using hydrosilanes as reductants, which provides efficient access to C-aryl and C-vinyl glycosides with excellent anomeric selectivity. The protocol features a broad substrate scope, excellent functional-group tolerance, and compatibility with both furanosyl and pyranosyl chlorides. Furthermore, the transformation is amenable to gram-scale synthesis and enables the late-stage functionalization of biologically relevant molecules. Mechanistic studies suggest the involvement of low-valent iron-aryl intermediates and glycosyl radicals in the catalytic cycle. These findings provide valuable insights into iron-catalyzed reductive coupling reactions and establish a foundation for the development of related iron-catalyzed methodologies for the synthesis of structurally diverse C-glycosides.