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JEE Advanced · 2020 · 27 Sep 2020 · Paper 1 · Chapter_pending

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In the reaction scheme shown below Q, R and S are the major products.

The correct structure of
  1. (A)S is (see structure)
  2. (B)Q is (see structure)
    ✓ Correct
  3. (C)R is (see structure)
  4. (D)S is (see structure)
    ✓ Correct

Answer: (B), (D)

Solution

Following the reaction sequence:
  1. Friedel-Crafts acylation with succinic anhydride gives Q (a keto-acid)
  2. Clemmensen reduction (Zn-Hg/HCl) reduces the ketone to CH₂, giving R
  3. Intramolecular Friedel-Crafts acylation forms a six-membered ring ketone
  4. Clemmensen reduction gives the final product S

Analyzing the structures:
  • Option (B) correctly shows Q with the keto-acid side chain
  • Option (D) correctly shows S as the final tetracyclic product

Options (A) and (C) show incorrect structures.

JEE Advanced · 2020 · 27 Sep 2020 · Paper 1 · One or more correct options

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