Use of Carbonyldiimidazole as an Activator of Formic Acid in a Tris(dibenzylideneacetone)dipalladium-Catalyzed Formylation of Aryl Iodides

Abstract A carbonyldiimidazole (CDI)-promoted generation of CO from formic acid has been exploited in a reductive formylation of aryl iodides in the presence of tris(dibenzylideneacetone)dipalladium. The reaction conditions are mild with a broad functional-group tolerance that includes keto, bromo, nitrile, ester, and nitro groups. In the reaction pathway, CDI reacts with formic acid to generate a formyl imidazole that ultimately produces the CO needed for the formylation process on the activated arylpalladium complex.