Palladium-Catalyzed Denitrative α-Arylation of Ketones with Nitroarenes.

The palladium-catalyzed α-arylation of ketones with readily available nitroarenes and nitroheteroarenes provides access to useful α-aryl and α-heteroaryl ketones. The use of the Pd/BrettPhos catalysts was critical to achieve high efficiency for these transformations, whereas other catalysts led to decreased yields or no conversions. The intramolecular type substrate was also applied in this methodology and gave a chromone derivative. Polyaromatic carbonyl compounds can be easily obtained by multicomponent tandem reactions, via nucleophilic aromatic substitution (SNAr) or cross-coupling reaction followed by this denitrative arylation. Kinetic experiments show that the electronic effect of nitrobenzenes has a greater effect on the reaction rate than the electronic effect of ketones.