Friedel-Crafts condensation of 4'-bromobiphenyl-4-ol (I) with 1-adamantanol (II) affords the adamantanylbiphenyl derivative (III). This is then subjected to Heck coupling with methyl acrylate (IV) to produce the biphenylyl acrylate (V). Finally, basic hydrolysis of ester (V) leads to the title carboxylic acid.
In an alternative method, 4-(t-butyldimethylsilyloxy)-3-(1-adamantyl)bromobenzene (I) undergoes Suzuki coupling with 4-formylbenzeneboronic acid (II) to provide the biphenyl aldehyde (III). Subsequent Wittig condensation of (III) with methyl triphenylphosphoranylideneacetate (IV) yields the unsaturated ester (V). This is finally hydrolyzed with LiOH to furnish the title compound.