Probing the arenium-ion (proton transfer) versus the cation-radical (electron transfer) mechanism of Scholl reaction using DDQ as oxidant

The re-examination of the controversial arenium-ion versus cation-radical mechanisms for Scholl reaction by using DDH/[H.sup.+] together with Fe[Cl.sub.3] as oxidants has shown that the reaction has proceeded via a cation-radical mechanism. The feasibility of the dicationic intermediate, formed by the loss of two electrons, is shown by its generation from a tetraphenylene derivative by using DDQ/[H.sup.+] as an oxidant.