Bridging of Bipyridine Units by Phenylphosphine Links: Linear and Cyclic Oligomers and Some Acid Derivatives

摘要

Reaction of 6,6'-dibromo-2,2'-bipyridine with phenylphosphine under palladium-promoted cross-coupling conditions provides a variety of linear oligomers bearing two reactive bromo substituents as well as a cyclic dimer,characterized by X-ray crystallography,in which the bipyridine units are constrained to a cis configuration by two phenylphosphine oxide bridges.Derivatives of the linear species containing both carboxylate and phosphonate substituents are readily obtained.