Efficient palladium-catalyzed synthesis of unsymmetrical donor-acceptor biaryls and polyaryls

Article abstract of DOI:10.1016/0022-328X(90)85107-A

4,4'-Unsymmetrically substituted biphenyls can be synthesized by cross-coupling reactions of substituted aromatic organometallic reagents and aromatic halides catalyzed by palladium complexes.This two-step method from commercially available aromatic halides has been used for the synthesis of a series of donor/acceptor para-substituted biphenyls, D-C6H4-C6H4-A, where D is an electron donor group and A an electron acceptor group, which are of interst as liquid crystal precursors and as having potential in non-linear optics.Biaryls in which the donor-phenyl moiety is replaced by a 2-furyl or 2-thienyl can be synthesized similarly.The method can also be used for the convergent synthesis of previously unreported unsymmetrically substituted polyparaphenylenes D-(C6H4)n-A (n = 3, 4).