Visible-Light-Catalyzed Regioselective Arylcarboxylation of Allenes with CO2

Abstract A visible-light-catalyzed arylcarboxylation of allenes with CO2 was developed using [Ir(ppy)2(dtbbpy)]PF6 (ppy = 2-phenylpyridine; dtbbpy = 4,4′-di-tert-butyl-2,2′-bipyridine) as a photocatalyst to synthesis β-aryl β,γ-unsaturated carboxylic acids. This multicomponent protocol proceeds in an atom-economical way with exclusive regioselectivity. Preliminary mechanistic experiments suggested that allylic carbanion species are the key intermediates.