Q26 · CSIR NET Chemistry, June 2011
Paper: CSIR NET June 2011 · Subject: Organic Chemistry · Chapter: Reagents, Reaction Mechanisms & Named Reactions · Topic: Reagents, Reaction Mechanisms & Named Reactions – General · Marks: 2 · Difficulty: Medium
The major product formed in the reaction given below is: 
$\mathrm{I_2/KI}$ 
$\mathrm{I_2/KI}$ (a)
(b)
(c)
(d)
Answer
Answer: A ✓ checked by 4AB · confidence high
The source book printed no answer; this one was worked out and checked — see the explanation.
Explanation
Iodolactonisation: I⁺ adds to the alkene and the carboxylate attacks anti, giving the cis-fused γ-lactone with iodine trans to the ring-oxygen (a).
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