A new MINDO/3 study of rearrangements in barbaralyl cations

Abstract

The MINDO/3 potential surface of some barbaralyl cations (R-C₉H₈⁺; R = H, CH₃, OH, C₆H₅, etc.) has been studied. Some MNDO and STO-3G calculations have also been performed. The results of the present work strongly suggest that cations with R = H, CH₃, Ph, and p-CH₃OC₆H₄ rearrange via intermediates but they do not undergo a direct process as previously proposed. Protonated barbaralone rearranges by a Cope mechanism. Activation energies calculated by MINDO/3 are in good agreement with experimental data.