Theoretical study on the nickel(0)-mediated coupling of carbon dioxide and benzylidenecyclopropane: Mechanism and selectivity

The mechanisms of the Ni(0)-mediated carboxylation of benzylidenecyclopropane with CO2 have been investigated by using DFT/B3LYP calculations. Among the various reaction pathways, the formation of five-membered cyclic Ni-carboxylate (2A′) via the bisligand route, leading to the target product cyclopropane derivative A, was found to occur easily in toluene. Alternatively, in acetonitrile the six-membered cyclic Ni-carboxylate 4B′d is the most probable species leading to the branched α,β-unsaturated ester B.