Room Temperature Palladium-Catalyzed 2-Arylation of Indoles

This communication describes the rational development of a PdII-catalyzed method for the direct 2-arylation of indoles using Ar-IIII-ArBF4. These reactions proceed under remarkably mild conditions (often at room temperature and in the presence of ambient air and moisture), and these features are believed to be the result of a PdII/IV mechanism operating in these systems. These transformations can be used to prepare functionally diverse 2-arylated indoles and pyrroles, and their potential utility has been expanded by the development of an in situ procedure for generating the iodine(III) arylating reagents.