Abstract
The catalytic oxidative domino degradation of phenols was investigated. Hydrogen peroxide (30% aq.) was used as an oxidant and 2,2′-dinitro-4,4′-ditrifluoromethyldiphenyl diselenide 4e as a catalyst. The products were muconic acid 5, and muconolactones muconolactones—5-carboxymethylfuran-2(5H)-ones 7 and 9. Phenols with alkyl groups at 2 or 4 positions of the benzene ring were converted regioselectively to corresponding muconolactones substituted at alkenylene ring carbon atoms. The reaction mechanism is proposed.
Notes
a Preparative yield.
b Unreacted substrate 1a was isolated almost quantitatively.
c 3,5-Di-tert-butyl-1,2-benzoquinone (3) was formed in up to 5.0% yield.
a Preparative yield. Data in parantheses were determined on 1H NMR analysis.
b Mixture of EZ and EE muconic acids were formed.
c 5a and 5b were determined on 1H NMR analysis in 1:3 ratio.
d 2-Methylmuconic acids 21a were determined on 1H NMR analysis in 1:1 ratio.
e EE-3-methylmuconic acid was formed.
f The reaction was prolonged to 72 h.