Oxidation of hydroquinones with 1 equiv, and 2,6-disubstituted phenols with 2 equiv, of thallium(III) nitrate (TTN) in methanol gives the corresponding p-benzoquinones in high yield. Oxidation of a variety of 4-alkyl- and 4-alkoxyphenols with 1 equiv of TTN in either methanol or trimethyl orthoformate (TMOF), on the other hand, gives 4-alkyl-4-methoxy- and 4,4-dimethoxycyclohexa-2,5-dienones in moderate to excellent yield. Formation of cyclohexadienones under these conditions is postulated to proceed via ipso thallation.
ASJC Scopus subject areas
- Organic Chemistry