10.1021/ja067144j.s001 Marc Lafrance Marc Lafrance Keith Fagnou Keith Fagnou Palladium-Catalyzed Benzene Arylation:  Incorporation of Catalytic Pivalic Acid as a Proton Shuttle and a Key Element in Catalyst Design American Chemical Society 2006 Catalytic Pivalic aryl bromides proton shuttle Key Element stoichiometric carbonate base reactivity arylation unactivated arene Proton Shuttle pivalate anion benzene bond 2006-12-27 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Palladium_Catalyzed_Benzene_Arylation_Incorporation_of_Catalytic_Pivalic_Acid_as_a_Proton_Shuttle_and_a_Key_Element_in_Catalyst_Design/3038530 A palladium−pivalic acid cocatalyst system has been developed that exhibits unprecedented reactivity in direct arylation. This reactivity is illustrated with the first examples of high yielding direct metalation−arylation reactions of a completely unactivated arene, benzene. Experimental and computational evidence indicates that the pivalate anion is a key component in the palladation/C−H bond breaking event, that it lowers the energy of C−H bond cleavage and acts as a catalytic proton shuttle from benzene to the stoichiometric carbonate base. Eight examples of substituted aryl bromides are included which undergo direct arylation with benzene in 55−85% yield.