A DFT Analysis of the Strain-Induced Regioselective[2+2]Cycloaddition of Benzyne Possessing Fused Four-Membered Ring

The regioselective [2+2] cycloaddition of a substituted benzyne possessing a fused four-membered ring to a ketene acetal has been theoretically studied. This cycloaddition presents a two-step mechanism that is initiated by the nucleophilic attack to the benzyne to give a zwitterionic intermediate. The analysis performed on the basis of the global and local electrophilicity of reagents correctly explain the observed reactivity and regioselectivity in this system.