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 pKa of the C‐H bond (more acidic position) and the lower distortion of chlorobenzene in the key transition structure.