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.