Arylation of Benzo-Fused 1,4-Quinones by the Addition of Boronic Acids under Dicationic Pd(II)-Catalysis

The first examples of the direct arylation of benzo-fused 1,4-quinones by the dicationic Pd(II)-catalyzed addition of arylboronic acids are reported. The addition reaction is carried out under very mild conditions (dioxane-H2O, rt, open air atmosphere) and is tolerant of free OH groups. In addition, the reaction shows high regioselectivity, when using nonsymmetrical quinones as starting materials.