Direct C–C Bond Formation of Allylic Alcohols with CO2 toward Carboxylic Acids by Photoredox/Nickel Dual Catalysis

Carboxylation of allylic alcohols with carbon dioxide is accomplished by photoredox/nickel dual catalysis, generating linear acids exclusively with good Z/E stereoselectivity. Hantzsch ester is employed as the reductant instead of stoichiometric metallic reductants, and the reaction can be conducted under room temperature with a blue LED light source. Mechanistic studies reveal that the presence of water in this catalytic system is critical to the success of the reaction, and the reaction is more likely to proceed in oxidative addition of the in situ formed allylic hydrogen carbonate.