JEE Main levelOne or more correct optionsDifficulty 2 of 3hc195
Which of the following statements about the Diels-Alder reaction are correct?
AIt is a concerted reaction with a single cyclic transition state
BIt is stereospecific with respect to the dienophile geometry
CIt proceeds through a free carbocation intermediate
DThe diene must be able to adopt the s-cis conformation
Answer: A, B, D
The reaction is a concerted pericyclic [4+2] process, so there is no carbocation (c wrong). Concertedness makes it stereospecific. The diene termini must be close together, which requires the s-cis conformation.