Catalytic Lactonization of Unactivated Aryl C–H Bonds with CO2: Experimental and Computational Investigation

The first catalytic lactonization of unactivated aryl C–H bonds with CO2 to afford important phthalides is reported. Notably, this method features high selectivity, excellent functional group tolerance, smooth scalability, and facile product diversification. DFT calculations reveal that a novel insertion of two CO2 into the O–Pd bond of a palladacycle might be the key step, providing great potential and a different perspective for carbonylation with CO2.