Which of the following compounds is the most reactive dienophile in a Diels-Alder reaction?

Question

Quizplus · Accepted Answer

Compound III is the most reactive dienophile as it has a strong electron-withdrawing nitro group, which increases the electrophilicity of the olefinic double bond carbon atoms, making it more susceptible to nucleophilic attack from the diene. It also has an electron-donating methoxy group at the para position, which increases the electron density at the aromatic ring, making it more prone to nucleophilic attack by the diene. This combination of electronic effects makes compound III the best dienophile in a Diels-Alder reaction.

Which of the Following Compounds Is the Most Reactive Dienophile