From Donor and Acceptor Substituted meta- and para-Xylenes to para-Quinodimethanes and Poly(meta-phenylenevinylene)s

Article abstract of DOI:10.1002/prac.19983400412

Ortho-, meta- and para-xylenes 1, 13a, 13b and 13c, with donor and acceptor substituents at the α- and α′ positions, lead to a remarkable variety of intermediates and reaction products after deprotonation of the benzylic proton. Thus, the reaction of para-(cyanomethyl)dialkyl[(methylthio)phenylmethylene]ammonium tetrafluoroborates 13a and 13b with sodium hydride affords the para-quinodimethanes 14a and 14b. Poly(meta-phenylenevinylene) 14c can be obtained when starting from 13c. We report the synthesis of para-quinodimethanes 14a and 14b and poly(meta-phenylenevinylene) 14c and describe a successive approach towards meta-phenylenevinylenes of definite length 16b and 17b starting from 12d. Moreover, we compare the stability and reactivity of para-quinodimethane 14a and 14b with those of the ortho-quinodimethane 2 and we focus on the characterization of the resulting donor and acceptor substituted compounds.