The oxidation of primary and secondary alcohols with ketones in the presence of metal alkoxides such as aluminum isopropoxide (Al(i-PrO)3) to yield aldehydes and ketones is known as the Oppenauer oxidation. The alcohol substrate binds to aluminum, and the ketone coordinates to it, forming a six-membered transition state that allows the alkoxide to transfer a hydride to the ketone, yielding a ketone and an i-propyl alcohol respectively. The reaction is reversible, favoring a large excess of the starting ketone.

  • Reagents: Metal Alkoxides (e.g. Aluminum Isopropoxide, t-Butoxide, or Phenoxide), Carbonyl Compound Oxidant (e.g. Acetone)
  • Reactant: Alkyl, Aryl, Alkenyl 1° or 2° Alcohol
  • Product: Ketone or Aldehyde, i-Propyl Alcohol
  • Type of Reaction: Oxidation

Lab Tips

This reaction requires high temperatures and long reaction times. Microwave irradiation instead of classical heating reduces reaction times; however, note that some studies suggest that NaOAc is not effective when using microwave irradiation and other bases should be considered. Moreover, studies suggest that if sodium acetate is used, it should be anhydrous.

Mechanism

Top Citations

Original Paper

Related Reactions

  • Meerwein-Ponndorf-Verley
  • Tishchenko Reaction
  • Synthesis of Aldehydes
  • Synthesis of Ketones

Related Compounds

  • Al(OiPr)3 (CAS 555-31-7)
By shuhan yang

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