Starting with ethyne, how will
you prepare pentan-2-one ?

Explanation

To prepare pentan-2-one starting from ethyne, we can follow these steps:

### Step 1: Formation of a Nucleophile
Start with ethyne (HC≡CH). Treat ethyne with sodium amide (NaNH2) to generate a nucleophile. The reaction will deprotonate ethyne to form the acetylide ion (HC≡C⁻).

**Reaction:**
\[ \text{HC≡CH} + \text{NaNH}_2 \rightarrow \text{HC≡C}^- \text{Na}^+ + \text{NH}_3 \]

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