Rapid construction of C4-substituted phenanthridinones through palladium-catalyzed domino N-arylation/aryl-aryl coupling process

An excellent chemo- and regioselective palladium-catalyzed cascade intermolecular N-arylation/aryl-aryl coupling process has been developed. Employing Pd(TFA)2, PCy3•HBF4, K2CO3 and 1,4-dioxane in an oil bath at 100°C for 12 h, diverse C4-substituted phenanthridinones are synthesized from o-bromobenzamides in 42-92% yield. Broad substrate scope and excellent functional group tolerance are observed. The synthetic utility of this method is illustrated by the further derivatization to prepare multiple-substituted phenanthridinones in 30-75% yield. © 2021