Palladium-catalyzed arylation of 1,4-naphthoquinones with aryl iodides and its synthetic application to the benzo[b]phenanthridine skeleton

We report a Pd-catalyzed arylation of 1,4-naphthoquinones with aryl iodides. This reaction shows excellent functional group tolerance and high regioselectivity when using nonsymmetric 1,4-naphthoquinone. Furthermore, the resulting 2-aryl-1,4-naphthoquinone could be successfully converted into benzo[b]phenanthridine-7,12-dione through treatment with aqueous ammonia, followed by oxidative cyclization using MnO2.