JEE Main 2022 · 30 Jun · Shift 1 · Chemistry Q76

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ChemistrySingle correct+4 / -1Question 76 of 90

Which among the following will be the major product of the given reaction ?

4,7-Dioxooctanoic acid, CH3-CO-CH2-CH2-CO-CH2-CH2-CO2H, treated with (i) 10% KOH, (ii) H3O+.

3-(2-Carboxyethyl)cyclopent-2-en-1-one

Cyclopent-2-enone with a CH2CH2CO2H chain on C3.

2-Methyl-3-(carboxymethyl)cyclopent-2-en-1-one

Cyclopent-2-enone with CH3 on C2 and CH2CO2H on C3.

4-Carboxy-3-methylcyclohex-3-en-1-one

Cyclohex-3-enone with CH3 and CO2H on the double bond carbons.

Spiro lactone (1-oxaspiro[4.4]nonane-2,7-dione)

Spiro compound: a cyclopentanone joined at one carbon to a five-membered lactone.

Answer and worked solution

Official answer: B

Intramolecular aldol of the 1,4-diketone $\mathrm{CH_3COCH_2CH_2COCH_2CH_2CO_2H}$ : the five-membered ring closes and dehydrates to 2-methyl-3-(carboxymethyl)cyclopent-2-enone.

(B)

Topics:Aldol and related condensations

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JEE Main 2022 · 30 Jun · Shift 1, Chemistry question 76