JEE Main 2017 · 2 Apr · Shift 1 · Chemistry Q60

← JEE Main 2017 · 2 Apr · Shift 1

ChemistrySingle correct+4 / -1Question 60 of 90

The major product obtained in the following reaction is :

A bicyclic γ-lactone fused to a cyclopentene ring that carries COOH on an alkene carbon, reacting with DIBAL-H.

A cyclopentene bearing CH₂CHO and COOH

A cyclopentene ring with CH₂-CHO on one carbon and COOH on the adjacent alkene carbon.

A cyclopentene bearing CH₂CHO and CHO

A cyclopentene ring with CH₂-CHO on one carbon and CHO on the adjacent alkene carbon.

A cyclopentene bearing OH, CH₂CHO and COOH

A cyclopentene ring with OH on one carbon, CH₂-CHO on the next and COOH on the adjacent alkene carbon.

A cyclopentene bearing OH, CH₂CHO and CHO

A cyclopentene ring with OH on one carbon, CH₂-CHO on the next and CHO on the adjacent alkene carbon.

Answer and worked solution

Official answer: C

DIBAL-H reduces the lactone to the lactol (hemiacetal) stage, which opens to an aldehyde and a free OH. The carboxylic acid is not reduced under these conditions. The product carries OH, $\ce{CH2CHO}$ and COOH, structure (3).

Topics:Acid derivatives Oxidation and reduction

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JEE Main 2017 · 2 Apr · Shift 1, Chemistry question 60