The reactions of cyclopropyl(methyl)bromonium ion with benzene in the gas phase
Abstract
The thermal gaseous cyclo-C3H5BrCH3+ ion, formed by the reaction of CH3ClCH3+ ion, but not of CH3FCH3+ ion, with cyclopropyl bromide, reacts with benzene as a methylating and as an allylating agent with equal facility. The loss of the cyclic structure results either from a concerted ring cleavage during the attack or from rearrangement of cyclopropylarenium ion after the attack. The methylating ability of cyclopropyl(methyl)bromonium ion toward benzene falls between those of dimethylfluoronium and dimethylchloronium ions, i.e. CH3FCH3+ > cyclo-C3H5-BrCH3+ > CH3ClCH3+.