Late‐Stage Cross‐Electrophile Coupling of Arylthianthrenium Salts with (Hetero)aryl (Pseudo)halides via Palladium Catalysis

Abstract Herein, we present a cross‐coupling reaction of arylthianthrenium salts at a late stage with diverse (hetero)aryl (pseudo)halides under reductive conditions, in which a palladium(0) catalyst differentiates between two aryl electrophiles based on the different rates of oxidative addition of arylthianthrenium salts and aryl halides for selective umpolung. A measured near‐zero Hammett rho value is consistent with oxidative addition of the arylthianthrenium salts to palladium(0) being insensitive to substituent effects, which enables reaction with structurally and electronically diverse arylthianthrenium salts. In addition, we show the robustness of this method by coupling of two complex fragments that would otherwise be difficult to access in a single step.