Electro-organic reactions. Part 41. Diels-Alder reaction of o-quinodimethanes from the cathodic reduction of α,α'-dibromo-1,2-dialkylbenzenes

Article abstract of DOI:10.1016/0040-4020(95)00034-6

Cathodic reduction of α,α'-dibromo-1,2-dialkylbenzenes in DMF containing ET₄N⁺ Br^- as supporting electrolyte, in the presence of dienophiles (e.g. maleic anhydride derivatives), yielded Diels-Alder adducts of o-quinodimethanes. Selective reduction of the benzylic dibromides was often possible even when their irreversible cyclic voltammetric reduction peak potentials were more negative than the E(o) values for the anhydrides. This might be a consequence of redox catalysis, with the anhydrides having a dual role as mediators and dienophiles.