Computational study on the mechanisms of [2+3] and [2+2] cycloisomerization reaction catalyzed by gold complex

Abstract The reaction mechanisms on the gold-catalyzed [2 + 3] and [2 + 2] cycloisomerization reaction have been computationally investigated by employing density functional theory (DFT) calculations. The stepwise addition of an olefin to the gold-allyl species followed by the selectivity-determining cyclization is calculated to be the most favorable mechanism, though this mechanism was considered as infeasible in the experiment. Our calculated results also support the Hammett analysis in the experiment by performing the mechanisms calculations through employing the substrates by substitution with electron-donating and electron-withdrawing groups. The regioselectivity for this reaction is clarified through our calculations.