Catalytic Oxidative Domino Degradation of Alkyl Phenols Towards 2- and 3-Substituted Muconolactones

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.

Keywords:

• Diselenides
• domino reaction
• hydrogen peroxide
• muconolactones
• oxidation

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.