Question

Reaction of 1,3- butadiene to maleic acid gives cis product while fumaric acid
gives trans product. Explain.

Answer 1

The Diels-Alder reaction is a conjugate addition reaction of a conjugated diene to an alkene (the dienophile) to produce a cyclohexene.

The Diels-Alder reaction is stereospecific:

 A cis dienophile will generate a ring with cis sustitution, while a trans dienophile will generate a ring with trans substitution.