JEE Main Chemistry question

Show the final product of the reaction: a ring-fused ketone bearing a pendant –CHO group --Zn(Hg)/HCl--> (A) --SOCl₂--> (B) --AlCl₃--> (C) --LiAlH₄--> (D) ←Alcoholic KOH– (G) ←NBS– (F) ←Conc.H₂SO₄– (E).

(A)A fused bicyclic aromatic hydrocarbon framework matching the standard polycyclic target of this classic multi-step synthesisCorrect
(B)An open-chain, non-cyclized product
(C)A partially reduced, non-aromatic bicyclic product
(D)A monocyclic product only

Answer: (A)

Solution

This is a classic multi-step total synthesis problem (Clemmensen reduction of a ketone to a methylene, conversion to the acid chloride, intramolecular Friedel–Crafts acylation to close a new fused ring, further reduction, then dehydrogenation/elimination/dehydration steps) that builds up a fused bicyclic aromatic-type

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Question ID VK-149486