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We have to identify the structure of its more stable conjugate base obtained by proton transfer of cyclohex-2-en-1-one.

Cyclohex-2-en-1-one

In the following question, there are two possibilities: We can either remove a hydrogen nearest to carbonyl group or remove a hydrogen next to carbon carbon double bond. I think the later should be correct as it involves higher conjugation, but the answer is the opposite, they have removed hydrogen which is nearest to carbonyl group. Why is this position preferred?

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  • $\begingroup$ The level of conjugation is the same, so inductive effects are most important here. $\endgroup$ – Zhe Jul 23 '18 at 13:39
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    $\begingroup$ Under kinetic conditions, deprotonation occurs at C6 to give an enolate that is not conjugated with the double bond. Under equilibration conditions, deprotonation occurs at C4 to give an extended, vinylogous enolate. The more stable conjugate base is the one formed under equilibrating conditions (leveling effect). $\endgroup$ – user55119 Jul 23 '18 at 14:56
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    $\begingroup$ You may want to look at: chemistry.stackexchange.com/questions/43007/… $\endgroup$ – user55119 Jul 23 '18 at 16:50

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