MolSynapsequestion bank
MolSynapse / Question bank / Hydrocarbons / Conjugated dienes and Diels-Alder reaction
JEE Advanced levelSingle correct optionDifficulty 3 of 3hc108

Isoprene reacts with methyl acrylate () in a Diels-Alder reaction. Assume the major product is the 'para' (1,4) regioisomer, in which the methyl group and the ester group are on ring carbons separated by two other carbons on each side. The major product is

  1. Amethyl 4-methylcyclohex-3-ene-1-carboxylate
  2. Bmethyl 2-methylcyclohex-3-ene-1-carboxylate
  3. Cmethyl 4-methylcyclohex-1-ene-1-carboxylate
  4. Dmethyl 3-methylcyclohex-3-ene-1-carboxylate

Answer: A

The ring consists of the four diene carbons and the two dienophile carbons, with the C=C between diene C-2 and C-3. The 1,4 ('para') relation puts the methyl-bearing diene carbon C-2 opposite the ester carbon. Numbering from the ester carbon as C-1 to give the double bond the lowest locant gives the C=C at 3,4, with methyl on C-4. The meta isomer would be the 3-methyl compound.
Practice Hydrocarbons More on Conjugated dienes and Diels-Alder reaction
Previous questionNext question

More questions on Conjugated dienes and Diels-Alder reaction