Polyphenyl Synthesis by Means of the Kharash-type Grignard Cross-coupling Reaction

抄録

A series of twenty-seven polyphenyls, including quater-to sexiphenyls, was synthesized by the cross-coupling reaction of aryl Grignard reagents with arylene diiodides in the presence of bis (acetylacetonato) nickel (II). Twenty of them were obtained in fairly good yields (50-95%) under mild conditions at temperatures below ca. 60°C in ether-benzene solution within a few hours. In the cases of the remaining seven polyphenyls, however, lower yields (1-34%) were inevitable owing to the sterically crowded geometry of the reactant (s). Thus, the Kharash-type Grignard cross-coupling reaction was proved to be an efficient and convenient method for synthesizing a variety of polyphenyls, except in the cases of reactants with remarkably crowded geometry. The infrared, ultraviolet, and proton magnetic resonance spectral properties of several polyphenyls including three new compounds, 3-(2-biphenylyl)-o-quaterphenyl, 6'-(3-biphenylyl)-m-quaterphenyl, and 3, 4'-di (2-biphenylyl) biphenyl, are presented and discussed.