Rearrangements of the thujan-3-yl cation

Abstract

Heterolysis of the C–O bond of the thujan-3-ols or their derivatives can give rise to either an undelocalised cation or a trishomocyclopropyl cation, depending on the alignment of the leaving group. In either case, a 1,2-hydride shift converts the ion into the bishomocyclopropyl cation. The reaction also yields iridane derivatives, formed by a different mechanism from that yielding the 2,3-dimethyl-1-(1-methylethyl)cyclopentyl cation in SO₂–HSO₃F at –50°.