Electroinduced Carbene Formation in the Cathodic Reduction of 1,2-Dicarbonyl Compounds via Electron-Transfer to the Solvent

• Electron-transfer reaction in solution from the substrate dianion to the solvent.
• To our knowledge, it is the first time that a carbene is generated by an electron-transfer in solution process.
• 1,1-Dichloroethyl radical and methyl-chlorocarbene as involved intermediates.
• The stereochemistry of the radical anion intermediate governs the reaction pathway.
• Electroinduced effect of reversible electroactive systems is presented.

Electrochemical reduction of 9,10-phenanthrenequinone, benzil and acenaphthenequinone in 1,1,1-trichloroethane (TCE)/TBAP under constant potential conditions provides an interesting entry to new coupling products through an electron-transfer reaction in solution to the chlorinated solvent. This electroinduced reaction points out the differences in the reaction pathway followed by these 1,2-dicarbonyl compounds depending on their geometry. The intermediates nature and their behavior, both in solution and at the electrode surface, are discussed.

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