A theoretical study on the competing mechanisms and regioselectivity of the intermolecular radical anion [2+2] cycloadditions of phenyl vinyl sulfone with enones

DFT (U)B3LYP/6-311+G(d,p) calculations have been carried out to investigate the competing mechanisms and regioselectivity of the intermolecular radical anion [2+2] cycloadditions of phenyl vinyl sulfone with enones. The dominating pathways of the cycloadditions are verified by comparing the activation barriers. The regioselectivity is found to be mainly caused by the p–π conjugation at one end of the CC double bond.