[2+2] Cycloaddition or beta-hydrogen elimination?-a DFT study of the reactions of propylene catalyzed by (PDI)Fe-metallacycle

The DFT method was used to investigate the mechanism of [2+2] cycloaddition reactions catalyzed by (PDI)Fe-metallacycle. The results indicated the origin of the chemoselectivity under different catalysts to be due more likely to the different groups (N-2 or CH3) coordinated with the core metal Fe, and not to the size of the specific substituent as speculated by experimenters.