Q17 · CSIR NET Chemistry, December 2017
Paper: CSIR NET December 2017 · Subject: Organic Chemistry · Chapter: Reagents, Reaction Mechanisms & Named Reactions · Topic: Named Reactions · Marks: 2 · Difficulty: Medium
Correct sequence of steps involved in the following transformation is 
(a)Michael addition, aldol condensation, syn elimination, keto-enol tautomerism
(b)aldol condensation, electrocyclic ring closing, syn elimination, dehydrogenation
(c)Michael addition, Claisen condensation, anti-elimination, keto-enol tautomerism
(d)Robinson annulation, dehydrogenation, anti-elimination
Answer
Answer: A ✓ checked by 4AB · confidence high
Explanation
Michael addition of the sulfoxide-stabilised enolate to EVK is followed by intramolecular aldol condensation. Syn (Ei) elimination of PhSOH and keto–enol tautomerisation then give the phenol (a).
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