4,4′-Biphenol is prepared by dealkylation of the tetra-t-butyl derivative, generated by the oxidative coupling of 2,6-di-tert-butylphenol. The oxidative coupling of phenol itself typically gives a mixture of isomers.[2] For example, VCl4 reacts with phenols give 4,4′-, 2,4′-, and 2,2′-biphenols:[3]
^Helmut Fiege; Heinz-Werner Voges; Toshikazu Hamamoto; et al. (2002). "Phenol Derivatives". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_313.
^O’Brien, M. K.; Vanasse, B. (2004). "Vanadium(IV) Chloride". In Paquette, L. (ed.). Encyclopedia of Reagents for Organic Synthesis. New York, NY: J. Wiley & Sons. doi:10.1002/047084289X.rv001.
^Dodds, E. C.; Lawson, W. (1937). "A Simple Aromatic (strogenic Agent with an Activity of the Same Order as that of strone". Nature. 139 (3519): 627–628. doi:10.1038/139627b0. ISSN0028-0836.