Question:medium

Consider the following reaction:
The product \(Y\) formed is:

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Vicinal dihalides give alkynes on treatment with excess \(\text{NaNH}_2\), and terminal alkynes can be alkylated via acetylide ions.
Updated On: Mar 26, 2026
  • 2-methylhex-3-yne
  • 2-methylhex-2-yne
  • 5-methylhex-2-yne
  • Isopropylbut-1-yne
Show Solution

The Correct Option is C

Solution and Explanation

To solve this question, we need to analyze the sequence of reactions given in the image. Let's break it down step by step:

  1. The starting compound is a dihalide: 2,3-dibromoheptane.
  2. The first step involves treatment with \(\text{NaNH}_2\), which is a strong base. This leads to the elimination of both bromine atoms, resulting in the formation of an alkyne.
  3. Reacting with a strong base like \(\text{NaNH}_2\) typically results in a double elimination to form an alkyne.
  4. The alkyne formed has the structure: \(\text{CH}_3-\text{C}\equiv\text{C}-\text{CH}_2-\text{CH}_3\), which is 2-heptyne.
  5. The next step involves another treatment with \(\text{NaNH}_2\), followed by reaction with an alkyl halide: \(\text{CH}_3\text{Br}\).
  6. Deprotonation by \(\text{NaNH}_2\) creates an acetylide ion, which can act as a nucleophile to attack the \(\text{Br}\) on the alkyl halide substituting \(\text{Br}\).
  7. This results in the formation of the compound 5-methylhex-2-yne.

Therefore, the correct product \(Y\) is 5-methylhex-2-yne. This aligns with the correct answer given:

5-methylhex-2-yne.

 

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