If (2Z,4Z)-hexa-2,4-diene were able to undergo a Diels–Alder reaction with methyl propenoate, what would be the products? (Hint: There are four products comprised of two pairs of enantiomers. One enantiomer pair would predominate.) In reality, this Diels–Alder reaction is impractical because the s-cis conformation of the diene required for the reaction is of high energy due to steric hindrance between the methyl groups.