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🥼organic chemistry review

Methyl Vinyl Ketone

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Methyl vinyl ketone is an organic compound with the chemical formula CH3C(O)CH=CH2. It is a colorless liquid with a sharp, unpleasant odor and is used as a building block in various organic synthesis reactions, including the Robinson Annulation Reaction.

5 Must Know Facts For Your Next Test

  1. Methyl vinyl ketone is a highly reactive compound due to the presence of both a carbonyl group and an alkene group, which allows it to participate in a variety of organic reactions.
  2. The Robinson Annulation Reaction utilizes methyl vinyl ketone as a key intermediate to construct cyclic compounds through a two-step process involving conjugate addition and cyclization.
  3. Methyl vinyl ketone can undergo nucleophilic addition reactions, such as conjugate addition, where a nucleophile adds to the β-carbon of the α,β-unsaturated carbonyl system.
  4. The cyclization step in the Robinson Annulation Reaction involves the intramolecular attack of the newly formed enolate on the ketone group, leading to the formation of a cyclic compound.
  5. Methyl vinyl ketone is a versatile building block in organic synthesis and is commonly used in the construction of various cyclic structures, including those found in natural products and pharmaceuticals.

Review Questions

  • Explain the role of methyl vinyl ketone in the Robinson Annulation Reaction.
    • Methyl vinyl ketone is a key intermediate in the Robinson Annulation Reaction, a two-step process used to construct cyclic compounds from acyclic precursors. In the first step, methyl vinyl ketone undergoes a conjugate addition reaction with a nucleophile, forming an enolate intermediate. This is followed by an intramolecular cyclization step, where the enolate attacks the ketone group, leading to the formation of a cyclic compound. The unique reactivity of methyl vinyl ketone, with both a carbonyl group and an alkene group, makes it a versatile building block in this important organic synthesis reaction.
  • Describe the reactivity of methyl vinyl ketone and how it allows for its use in various organic reactions.
    • Methyl vinyl ketone is a highly reactive compound due to the presence of both a carbonyl group and an alkene group. The carbonyl group makes it susceptible to nucleophilic addition reactions, such as the conjugate addition step in the Robinson Annulation Reaction. The alkene group allows methyl vinyl ketone to participate in electrophilic addition reactions and other transformations. This dual reactivity makes methyl vinyl ketone a valuable intermediate in organic synthesis, as it can be used to construct a wide range of cyclic and acyclic compounds through a variety of reaction pathways, including the key cyclization step in the Robinson Annulation Reaction.
  • Analyze the importance of the cyclization step in the Robinson Annulation Reaction and how it is facilitated by the use of methyl vinyl ketone as a key intermediate.
    • The cyclization step in the Robinson Annulation Reaction is a crucial part of the overall transformation, as it allows for the construction of cyclic compounds from acyclic precursors. This step is facilitated by the use of methyl vinyl ketone as a key intermediate, which undergoes a conjugate addition reaction in the first step, forming an enolate. The enolate then undergoes an intramolecular attack on the ketone group, leading to the formation of the desired cyclic compound. The unique reactivity of methyl vinyl ketone, with its carbonyl and alkene functionalities, enables this cyclization to occur, making it an indispensable component of the Robinson Annulation Reaction. The ability to construct complex cyclic structures through this reaction highlights the importance of methyl vinyl ketone as a versatile and valuable building block in organic synthesis.