Palladium-catalyzed arylation of methylene-bridged polyarenes: Synthesis and structures of 9-arylfluorene derivatives

In the presence of a catalytic system comprised of palladium(II) acetate and tricyclohexylphosphine, the reaction of fluorene with haloarenes generated 9-arylfluorenes in good to excellent yields. The scope and limitations of the coupling reaction were investigated. This synthetic protocol is more efficient than conventional methods. A wide range of functional groups, including alkyl, alkoxy, ester, and nitrile, can tolerate the reaction conditions herein. Sterically congested haloarenes also gave satisfactory results. Furthermore, this synthetic method is utilized to prepare 9,9-diarylfluorenes and tetraarylindenofluorene. Depending on the reaction conditions, the arylation of bowl-shaped sumanene gave monoarylated sumanene either as the sole product or with another diaryl-substituted product.