Selectivity Switch in Non‐Directed Palladium‐Catalyzed C−H Olefination of Chlorobenzene Derivatives

Abstract A palladium(II)‐catalyzed oxidative C−H olefination of chlorobenzene derivatives, which favored the functionalization at the ortho ‐to‐chlorine position, was reported. The catalytic system employed a commercially available quinoline ligand to access a wide panel of olefinated aryl chlorides in moderate to high yields from feedstock chemicals (42 examples, 28 to 93% yields). The synthetic utility of the method was further demonstrated by the coupling of various bio‐relevant acrylate partners offering straightforward access to structurally diverse complex molecules. A computational study of the reaction allowed us to confirm that the C−H activation step, occurring through a Concerted Metalation‐Deprotonation mechanism, determined the site‐selectivity of the transformation. The regioselectivity was controlled by the p K a of the C−H bond (more acidic position) and the lower distortion of chlorobenzene in the key transition structure.