ELECTROSYNTHESIS OF UNSYMMETRICAL POLYARYLS BY A S(RN)1-TYPE REACTION

Unsymmetrical polyaryls are electrosynthesized in liquid ammonia by a single-step S(RN)1 reaction in the presence of a redox mediator starting from aromatic halides and 2,6-di-tert-butyl phenoxide. With monoaryl halides activated by electron-withdrawing substituents (N of pyridyl or quinolyl, trifluoromethyl, cyano, sulfone, ester, ketone, alkyl sulfide, N+ of anilinium), biaryls are obtained in good yields (between 50 and 95%). The yields of ter- and quateraryls are lower (40% maximum). The reaction is extended to other ortho-disubstituted phenols. Elimination reactions of the tert-butyl groups from the products are achieved by a Friedel-Crafts reaction using either trifluoromethanesulfonic acid or aluminum trichloride as catalysts.