The copper–amine catalysed autoxidation of phenols. Part I

Oxidative Dearomatization of Phenols: Why, How and What For?

“…Such a proposal does indeed appear quite logical, but proving that an ortho-quinol either follows or precedes its phenolic counterpart during biosynthesis is not a trivial matter. 108 In any event, it is clearly much more reasonable 117 the Mimoun molybdenum complex 118 and PIDA 119 are among some of the reagents that have been used with some success. Which one did we start with?…”

Aerobic Copper-Catalyzed Organic Reactions

“…707 Treatment of the ortho - ortho -coupled product with CuCl 2 and pyridine in the presence of oxygen and KOH in methanol also leads only to the benzooxetane product. 715 …”

“…The oxidation of 2,6-di- tert -butyl-4-methylphenol with copper(II) chloride requires slightly higher catalyst loading than 2,4-di- tert -butyl-6-methylphenol (Scheme 487). 715 …”

“…Treatment of methylated hydroquinones with CuCl-pyridine in methanol under oxygen results in oxidative nucleophilic addition of solvent to generate a ketal (Scheme 491). 715 When the reaction is conducted in the presence of a secondary amine such as morpholine, the oxidative dearomatization results in a aminal. When no ortho - or para -methoxy group is present relative the phenol, the oxidative dearomatization reaction results in addition of solvent to the least hindered ortho - or para -position (Scheme 492).…”

Oxidative Conversion of Arenols into ortho ‐Quinols and ortho ‐Quinone Monoketals – A Useful Tactic in Organic Synthesis

“…Radical-mediated CaO coupling reactions of aryloxy radicals can, of course, lead to orthoquinol derivatives, but the preparative value of such an approach is poor and essentially limited to intramolecular cases. For example, certain bis-phenols such as 36a-c have been spiroannulated in good yields by diradical CaO coupling under favorable one-electron oxidation regimes ( Figure 12) [65][66][67].…”