Improved Syntheses of 3,5-Diaryl-Substituted Phenols

Abstract

[3+3] Annulation reaction of 1-(benzotriazol-1-yl)propan-2-one with 1,3-diarylprop-2-enones under basic conditions gave a series of 3,5-diaryl-substituted phenols in high yields (52-94%). The intermediate benzotriazole-substituted cyclohex-2-enones were isolated in two cases; the X-ray structure of intermediate 3-(4-methoxyphenyl)-5-(4-methylphenyl)-6-(benzotriazol-1-yl)cyclohex-2-enone is discussed. The intermediates rapidly lose benzotriazole under the action of strong base, thus leading to the formation of phenols. A conventional one-pot sequence of the reaction allows to prep. a variety of 3,5-diaryl-substituted phenols, including 3-(o-substituted-aryl)phenols which could not be prepd. by known procedures. [on SciFinder(R)]