The reaction between X and Y to give Z proceeds via X + Y Z · ABC26OR0561
Subject: Organic Chemistry · Chapter: Pericyclic Reactions · Topic: Cycloaddition Diels Alder · Exam: GATE 2000-2022 · Marks: 2 · Difficulty: Easy
The reaction between X and Y to give Z proceeds via 
X + 
Y 
Z
X + Y Z(a)$4 \pi$-conrotatory opening of X followed by endo Diels - Alder cycloaddition.
(b)$4 \pi$-disrotatory opening of X followed by endo Diels - Alder cycloaddition.
(c)$4 \pi$-conrotatory opening of X followed by exo Diels - Alder cycloaddition.
(d)$4 \pi$-disrotatory opening of X followed by exo Diels - Alder cycloaddition.
Answer
Answer: A ✓ checked by 4AB · confidence medium
The source book printed B; on checking, A is correct — see the explanation.
Explanation
Thermal 4π conrotatory opening of trans-diphenylbenzocyclobutene gives the (E,E)-o-xylylene with both Ph outward. Endo Diels–Alder with maleic anhydride then gives Z with the two Ph cis to each other (a).
Study loop for Pericyclic Reactions