Moderate

Aldol condensation is not successful with compounds:

Correct answer: A. Having no a-hydrogen

  • A. Having no a-hydrogen
  • B. Having a-hydrogen
  • C. Having a methyl group
  • D. Difficult to predict

Explanation

Option A is correct.A carbonyl compound must have at least one alpha-hydrogen to undergo aldol condensation. The base-catalyzed mechanism begins with the abstraction of an acidic α-hydrogen to form an enolate ion. This enolate then acts as a nucleophile and attacks the carbonyl carbon of another molecule.Compounds with no α-hydrogen cannot form an enolate ion and therefore cannot undergo typical aldol self-condensation.

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About Aldehydes and Ketones

Aldehydes and ketones contain the polar carbonyl group, but aldehydes are generally more readily oxidised and more reactive than ketones. Coverage includes preparation by oxidation or reduction routes, nucleophilic addition of reagents such as hydrogen cyanide and bisulfite, and tests that distinguish aldehydes from ketones.

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