Question

Question: Explain why methyl vinyl ether $\left({\mathrm{CH}}_2={\mathrm{CHOCH}}_3\right)$ is not a reactive dienophile in the Diels-Alder reaction.

Short answer

Answer

The resonance structure of methyl vinyl ether has a less electrophilic negatively charged carbon that does not react effectively as a dienophile in a Diels-Alder reaction.

Step-by-step solution

Diels-Alder reaction

It is the reaction between a diene and a dienophile to form a six-membered ring.

Dienophile

Dienophile reacts with the conjugated double bonds to form a ring.

Explanation

In the resonance structure of methyl vinyl ether, the lone pair of oxygen is moved on to the double bond, which increases the electron density on the double bond. The double bond hence acts less effectively as an electrophile in the Diels-Alder reaction.

Resonance structure of methyl vinyl ether