Electrochemical synthesis of dimerizing and nondimerizing orthoquinone monoketals

J Org Chem. 2004 Dec 10;69(25):8731-8. doi: 10.1021/jo048677i.


Anodic oxidation of appropriately substituted 2-methoxyphenols or alpha-(2-methoxyphenoxy)-2-methylpropionic acids in the presence of methanol furnishes stable orthoquinone monoketals, and thus constitutes a valuable alternative to the use of chemical oxidants that are often based on toxic metallic species. The propionic acid derivatives are initially converted into O-spirolactonic quinone bisketals that are then selectively hydrolyzed into the desired monoketal compounds. In the absence of blocking substituents, orthoquinone monoketals spontaneously undergo Diels-Alder dimerizations into tricyclododecadienedienones with extraordinary site selectivity, regioselectivity, and stereoselectivity. Suggestions are made to open up a new track for a long awaited rationalization of these controls on the basis of the intramolecular [2 + 2] reactivity of these orthoquinone monoketal-derived cyclodimers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Dimerization
  • Electrochemistry
  • Ketones / chemical synthesis*
  • Oxidation-Reduction
  • Quinones / chemical synthesis*
  • Stereoisomerism


  • Ketones
  • Quinones