Regioselective Ni-Catalyzed Carboxylation of Allylic and Propargylic Alcohols with Carbon Dioxide

An efficient Ni-catalyzed reductive carboxylation of allylic alcohols with CO₂ has been successfully developed, providing linear β,γ-unsaturated carboxylic acids as the sole regioisomer with generally high <i>E</i>/<i>Z</i> stereoselectivity. In addition, the carboxylic acids can be generated from propargylic alcohols via hydrogenation to give allylic alcohol intermediates, followed by carboxylation. A preliminary mechanistic investigation suggests that the hydrogenation step is made possible by a Ni hydride intermediate produced by a hydrogen atom transfer from water