Alkylation of Catechol with Benzhydrol: Unusual Regioselectivity in the Synthesis of o‐Quinones and Catechols

Unusual regioselectivity occurs in the alkylation reaction of benzhydrol with catechol. The reaction proceeds to give catechols containing two vicinal diphenylmethyl substituents. 4,5-Bis-(diphenylmethyl)-substituted catechol was found as the main product in more than 50 % yield. The reaction outcome is quite different to that of the reactions using bulky alkyl alcohols reported so far, in which 3,5- and 3,4,6-disubstituted species were formed predominantly. The minor products this reaction are 3,5-di- and 3,4,6-trisubstituted species. Di- and trialkylated catechols were oxidized to give the corresponding o-quinones. The reactivity and physicochemical properties of the new compounds were studied.