Triethanolamine-Mediated Palladium-Catalyzed Regioselective C-2 Direct Arylation of Free NH-Pyrroles

An atom-economical phosphane-free palladium-catalyzed direct C-2 arylation of unactivated free NH-pyrroles is devised. This method provides a straithforward route to a wide variety of substituted 2-aryl-1H-pyrroles from readily accessible starting materials. Iodoarenes bearing electron-withdrawing and electron-donating substituents are tolerated under the presented reaction conditions. The scope of the reaction is also expanded to N-aryl and -alkylpyrroles albeit in lower yields.