Mechanistic Comparison between Pd-Catalyzed Ligand-Directed C-H Chlorination and C-H Acetoxylation

This communication describes detailed investigations of the mechanism of the Pd-catalyzed C-H chlorination and acetoxylation of 2-o-tolylpyridine. Under the conditions examined, both reactions proceed via rate-limiting cyclopalladation. However, substrate and catalyst order as well as Hammett data Indicate that the intimate mechanism of cyclopalladation differs significantly between PdCl2-catalyzed chlorination and Pd(OAc)(2)-catalyzed acetoxylation.