Synthesis of α‐Quaternary Carboxylic Acids through Cu‐Catalyzed Hydrocarboxylation of Allenes with Diisobutylaluminum Hydride and Carbon Dioxide

Abstract A regioselective method for synthesizing β,γ‐unsaturated α‐quaternary carboxylic acids through the copper‐catalyzed hydrocarboxylation of allenes with CO 2 is described. Allenes undergo hydroalumination with diisobutylaluminum hydride, followed by carboxylation of the resulting allylaluminum intermediate. The presence of an N ‐heterocyclic carbene ligand is essential for enhancing the reactivity of the reaction. The good functional group compatibility of the reaction allows the synthesis of a wide range of functionalized α‐quaternary carboxylic acids with high regio‐ and stereoselectivities for synthetic and medicinal applications.