Dual Role of Aryl Iodide in Cascade C–H Arylation/Amination: Arylation Reagent and Cocatalyst for C–N Formation

A cascade C–H arylation/amination protocol using homoallylic primary amines as the starting materials in the presence of a palladium catalyst produces 2-aryl-1-pyrrolines with excellent regioselectivity and in good yields. Mechanistic studies indicate that this transformation proceeds via palladium-catalyzed Heck coupling, C–H amination, and tautomerization. As an unprecedented example of aryl iodide acting as an arylation reagent and a cocatalyst, the key role of aryl iodide as a cocatalyst is to generate the active bivalent aryl palladium catalyst to promote C–N formation during the C–H amination step.