Mechanistic study of nickel-catalyzed intramolecular [4 + 2] cycloaddition of cyclobutanone with allene: origin of selectivity and ligand effect

The transition metal catalyzed cycloaddition reaction is one of the most powerful tools for the construction of carbon- and heterocycles. DFT studies are performed to investigate the mechanism of the Ni-catalyzed intramolecular [4 + 2] cycloaddition.