[figure] Product P is
- [figure]
- [figure]
- [figure]
- [figure]
Answer
(4) [figure]
Solution
[figure]
∵ alc. KOH, Δ ⇒ E2 (dehydrohalogenation); H is removed from the benzylic CH2 (β-carbon)
⇒ C=C conjugated with the benzene ring (resonance-stabilised, most stable alkene)
Loss of the other β-H would give a non-conjugated alkene (less stable) ⇒ minor
Answer: (4)