Which of the following shows keto-enol isomer | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(B) For a compound to exhibit keto-enol isomerism,it must possess at least one $\alpha$-hydrogen atom adjacent to the carbonyl group $(C=O)$.$1$. Opti

Vedclass · Accepted Answer

Vedclass · Answer

(B) For a compound to exhibit keto-enol isomerism,it must possess at least one $\alpha$-hydrogen atom adjacent to the carbonyl group $(C=O)$.$1$. Option $A$ ($4$,$4$-dimethylcyclohexa$-2,5-$dien$-1-$one): The carbon adjacent to the carbonyl group is quaternary (bonded to two methyl groups),so it has no $\alpha$-hydrogen.$2$. Option $B$ (cyclohexa$-2,5-$dien$-1-$one): The carbons adjacent to the carbonyl group are $CH$ groups,which possess $\alpha$-hydrogen atoms. These hydrogens are acidic and can participate in keto-enol tautomerism.$3$. Option $C$ ($2$,$2$-dichlorocyclohex$-2-$en$-1-$one): The $\alpha$-carbon is bonded to two chlorine atoms,so it has no $\alpha$-hydrogen.$4$. Option $D$ (spiro[$5.5$]undeca$-1,4-$dien$-3-$one): The $\alpha$-carbon is a quaternary spiro carbon,so it has no $\alpha$-hydrogen.Therefore,only the compound in option $B$ shows keto-enol isomerism.

Column-$I$	Column-$II$
$A$. Acetaldehyde,vinyl alcohol	$1$. Enantiomers
$B$. Eclipsed and staggered ethane	$2$. Tautomers
$C$. $(+)$$2$-butanol,$(-)$$2$-butanol	$3$. Chain isomers
$D$. Methyl-$n$-propylamine and diethylamine	$4$. Conformational isomers
	$5$. Metamers

Which of the following shows keto-enol isomerism?

Similar Questions

$Ph-C(ClF_2)=C(F)_2 \xrightarrow{1\,eq. \, ^-OEt} A$ (major product),$A$ is

Which of the following is correct for the given molecule?

Which of the following orders is correct for the heat of hydrogenation of these compounds?

The stable form of $trans-1,4-$dimethylcyclohexane is represented as:

Vedclass Test Series

Exam Paper Generator

Online Exam Module