Ethyl 3-oxobutanoate (ethyl acetylacetate), can be obtained by Claisen from ethyl acetate, and is a very efficient reagent for the preparation of ketones.

 
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Butanone [2] can be obtained from ethyl acetylacetate [1] through the indicated stages.
 
Stage 1. Formation of the ketoester enolate
 
sintesis-acetilacetica
 
Stage 2 . Nucleophilic attack of the ketoester enolate on the haloalkane.
 
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Stage 3. Hydrolysis of the ester
 
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Stage 4. Decarboxylation
 
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