A One-Pot Synthesis of m-Terphenyls via a Two-Aryne Sequence

Article abstract of DOI:10.1021/jo00366a016

Aryl-Grignards (3⁺ equiv) react with 2,6-dibromoiodobenzene or other 1,2,3-trihalobenzenes to give 2,6-diarylphenylmagnesium halides.The mechanism involves Grignard exchange at the central halogen, followed by two cycles of magnesium halide loss and regioselective capture of the resulting aryne by the aryl-Grignard reagent (Scheme I).Typical examples are shown in Table I.The method is especially applicable to m-terphenyls in which the "outer" rings are identical and/or in which substitution at the 2' or other positions of the "central" ring is desired.