Mechanism for Three-Component Ni-Catalyzed Carbonyl–Ene Reaction for CO2 Transformation: What Practical Lessons Do We Learn from DFT Modelling?

In the present study, we use computational quantum chemistry to examine the nickel-catalyzed three-component coupling for transforming CO2 into a homoallylic alcohol. We find that the reaction is limited by several Ni-assisted atom transfer reactions in the catalytic cycle, in which a new product formation pathway is found from our calculations. Our results also point towards several key factors for an efficient reaction. Thus, substrates that would lead to a stabilized alkene facilitate a key step in the catalytic cycle. The optimal phosphine ligand should provide a good balance between directing stereochemistry with its steric bulk and enabling the reaction without being excessively bulky. Our calculations also highlight the importance of carefully chosen substrates and ligands in order to avoid potential side reactions, and that knowing the conformational preference in the substrate alone may not be sufficient for predicting the stereochemistry.