In three distinct steps, the Robinson annulation converts a ketone and an α,β-unsaturated ketone into a substituted cyclohexenone compound. First, the base creates an enolate ion intermediate, which reacts with the α,β-unsaturated ketone in a conjugate 1,4 addition (Michael reaction) to form a 1,5 diketone. An intramolecular aldol reaction occurs next, affording a cyclic β-hydroxy ketone. A final base-catalyzed dehydration affords the cyclohexenone product.

  • Reagents: Base, Ethanol
  • Reactant: Ketone, α,β-Unsaturated Ketone
  • Product: Substituted Cyclohexenone
  • Type of Reaction: Carbonyl Condensation Reaction (Michael and Intramolecular Aldol)
  • Bond Formation: C-C (α-carbon of the ketone and the β-carbon of the unsaturated ketone) and C=C

Lab Tips

  • This reaction can also be acid-catalyzed.
  • Although a one-pot process is possible, yields tend to be higher when the Michael adduct is isolated and then subjected to the aldol reaction.
  • The Michael reaction works best when a stable enolate ion adds to an unhindered α,β-unsaturated ketone.
Kürti, L., Czakó, B. (2005). Strategic Applications of Named Reactions in Organic Synthesis; Background and Detailed Mechanisms. Burlington, MA: Elsevier Academic.


Top Citations

Original Paper

Related Reactions

  • Michael Addition
  • Aldol Condensation
  • Aldol Addition

Related Compounds

  • Ketone
  • Ethanol (CAS 64-17-5)
  • Base
By shuhan yang


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