Cationic Cobalt(III)-Catalyzed Aryl and Alkenyl CH Amidation: A Mild Protocol for the Modification of Purine Derivatives

A cationic cobalt(III)‐catalyzed direct CH amidation of unactivated (hetero)arenes and alkenes by using 1,4,2‐dioxazol‐5‐ones as the amidating reagent has been developed. This transformation proceeds efficiently under external oxidant‐free conditions with a broad substrate scope. Moreover, 6‐arylpurine compounds, which often exhibit high potency in antimycobacterial, cytostatic, and anti‐HCV activities, can be smoothly amidated, thus offering a mild protocol for their late stage functionalization. Operationally simple: A cationic cobalt(III) catalyzed direct CH amidation of unactivated (hetero)arenes and alkenes has been developed (see scheme; DCE=1,2‐dichloroethane). This reaction proceeded efficiently under external oxidant‐free conditions with ample substrate scope, as well as excellent chemo‐ and regioselectivity. Moreover, 6‐arylpurine compounds, which often exhibit important biological activities, can be smoothly modified by this mild protocol.