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JEE Main · 2021 · 24 Feb 2021 · Shift 1 · Alcohols Phenols and Ethers

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Identify products A and B .

  1. (A)(see structures)
    Structure A
    A
    Structure B
    B
  2. (B)(see structures)
    Structure A
    A
    Structure B
    B
    ✓ Correct
  3. (C)(see structures)
    Structure A
    A
    Structure B
    B
  4. (D)(see structures)
    Structure A
    A
    Structure B
    B

Answer: (B)

Solution

The reaction shown involves the ozonolysis of a cyclic alkene followed by reductive workup.

In the first step, ozone () adds across the double bond to form a molozonide, which rearranges to an ozonide. The reductive workup with cleaves the ozonide to give carbonyl compounds.

For the given cyclic structure with a methyl substituent, ozonolysis cleaves the ring at the double bond. The reductive workup produces:
  • Product A: A cyclic diol (1-methylcyclopentane-1,2-diol) where both carbons of the former double bond are converted to hydroxyl groups.
  • Product B: A cyclic ketone-alcohol (2-methylcyclopentanone with a hydroxyl group).

Based on the mechanism and the structures shown in option (2), where A shows the gem-diol structure and B shows the keto-alcohol structure, option (2) is correct.

JEE Main · 2021 · 24 Feb 2021 · Shift 1 · Single correct option

Practise more: all JEE Main PYQs on Alcohols Phenols and Ethers →

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