Enabling Aryl Chloride-Mediated Palladium/Norbornene Cooperative Catalysis.

While the palladium/norbornene (Pd/NBE) cooperative catalysis has become increasingly useful for arene functionalization, its substrate scope has been mainly restricted to reactive aryl iodides and bromides. Despite being a more available and attractive feedstock, common aryl chlorides have not been used as substrates for the Pd/NBE catalysis. Herein, we report the first general Pd/NBE-catalyzed vicinal difunctionalization of aryl chlorides. Enabled by the combination of secondary-amide-substituted NBEs and XPhos ligand, diverse aryl chlorides can now undergo successful ortho alkylation, amination, and acylation with different ipso terminations, including olefination, hydrogenation, and alkynylation. To show the utility of this method, late-stage derivatizations of complex bioactive compounds and sequential functionalizations of polyhaloarenes have been achieved.