Catalyst Control of Site Selectivity in the PdII/IV-Catalyzed Direct Arylation of Naphthalene

This letter describes a new method for the highly site- and chemoselective Pd-catalyzed direct arylation of naphthalene. Tuning the structure of the diimine-ligated Pd catalyst results in formation of the α-arylated product in high yield and >50:1 selectivity. This is, to our knowledge, the first systematic evaluation of catalyst control in the C−H arylation of an unactivated aromatic substrate. Preliminary studies implicate an unusual mechanism involving sequential naphthalene π-coordination/metalation at PdIV.