Hydrogenation of 4-Substituted Biphenyls

Article abstract of DOI:10.1021/jo00385a018

Hydrogenations of 4-hydroxy-(1a), 4-methoxy-, and 4-methylbiphenyls were carried out in the presence of Raney nickel (R-Ni), palladium-on-carbon (Pd-C), or platinum as catalysts under relatively mild conditions.The reaction rates depend primarily on the catalysts and less on the substrates.Hydrogenation with Pd-C or Pt took place predominantly in the phenyl ring, independent of the substituent.On the other hand, hydrogenation with R-Ni caused reduction mainly in the substituted aromatic ring.Hydrogenation of the phenol, 1a, using R-Ni afforded predominantly trans-4-phenylcyclohexanol in preference to the cis isomer, differing from the other reactions examined.