QUINONES AND QUINONE METHIDES .5. FURTHER REARRANGEMENTS OF THE DIMER FROM 5-METHOXY-2-(4-METHOXYPHENYLMETHYL)-1,4-BENZOQUINONE

In strongly acid solutions the dimer 3 dissociates to the quinone 1 and quinone methide 2 which recombine with elimination of p-methoxybenzyl alcohol to form the xanthylium salt 9a. With zinc and acetic acid 3 yields isormeric meso- and dl-ethylenediquinol derivatives 14a. Sodium borohydride reduction of 3 yields an alcoholic quinol 5a which rapidly reoxidizes to the spiro-tetrahydrofuran derivative 24a. Possible mechanisms which may be involved in the formation of these rearranged products are discussed. © 1979.