Iodide Anion Modulates Halide Equilibrium in Cobalt-Catalyzed Cross-Electrophile Coupling to C -(Hetero)aryl Glycosides

Abstract

C-(Hetero)aryl glycosides are privileged in pharmaceutical chemistry, yet their stereoselective synthesis remains challenging. We report an iodide-anion-enabled cobalt-catalyzed reductive cross-electrophile coupling of glycosyl chlorides with (hetero)aryl bromides, affording C-(hetero)aryl glycosides with high efficiency and stereoselectivity. Mechanistic studies reveal that iodide modulates halide coordination at cobalt, preventing Co–Cl deactivation and enabling the formation of the active L9–CoI2(II) species. This work establishes iodide as a multifunctional promoter in cobalt-catalyzed C-glycosylation.