Visible-light-promoted regioselective hydrocarboxylation of allenes with formate salt and CO2.

Visible-light-promoted hydrocarboxylation of allenes with formate salt and CO2 was developed for the first time using commercially available [Ir(ppy)2(dtbbpy)]PF6 as a photocatalyst. This strategy provides an efficient and practical method to access β,γ-unsaturated linear carboxylic acids in moderate yields with complete regioselectivity.