Palladium-Catalyzed intramolecular direct arylation of aromatic tertiary amide compounds revisited

Abstract

We have investigated the palladium-catalyzed intramolecular direct arylation of three aromatic tertiary amide compounds. For the C–H activation of the benzene ring, heating over 120 °C in the presence of PCy3·HBF4 and PivOH was indispensable, and the formation of the regioisomer could not be suppressed. The introduction of a branched alkyl chain hampered the smooth reaction. In contrast, the C–H activation of the pyridine ring proceeded even at 100 °C, and the target compound was obtained quantitatively. These results were qualitatively supported by theoretical DFT calculations.