Palladium-catalyzed synthesis of nonsymmetrically functionalized bipyridines, poly(bipyridines) and terpyridines

Palladium-catalyzed coupling reactions were employed to prepare nonsymmetric, densely functionalized bipyridines and oligo(bipyridines), featuring sensitive functionalities like alcohol, ester and aldehyde groups. Stille coupling between halo (poly)pyridine and the proper (poly)pyridyltin derivative afforded in good yields nonsymmetric, derivatized oligo(bipyridines), amenable to further synthetic modifications. The methodology was used also to synthesize highly functionalized terpyridines. A series of Suzuki and Stille palladium-promoted coupling reactions allowed us to obtain in good yields terpyridines bearing two different and differently functionalizable groups, valuable building blocks for the construction of complex supramolecular frameworks. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).