A Palladium NCP Pincer Complex as an Efficient Catalyst for Intramolecular Direct Arylation

CH functionalization is a convenient methodology with broad application in total synthesis and medicinal chemistry that provides the same products as already well established cross-coupling methodologies, but with the advantage of avoiding the use of metallic species such as Grignard, boron, silicon and tin compounds. Herein, we report an unprecedented palladium-catalyzed intramolecular direct arylation for the general access of phenanthridinones under very low catalyst loadings. With only 0.05 mol%, a palladium NCP pincer complex promotes efficiently the direct functionalization of a series of N-arylbenzanilides and N-arylsulfonamides which constitutes an effective, versatil and environmentally attractive procedure for the preparation of phenanthridinones, biaryl sultams and related heterocyclic derivatives.