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Self condensation of two moles of ethyl acetate in presence of sodium ethoxide yields :-
A
Ethyl butyrate
B
Acetoacetic ester
C
Methyl acetoacetate
D
Ethyl propionate
Detailed Solution
Esters having $\alpha$-hydrogen atoms undergo self condensation in the presence of a strong base such as sodium ethoxide. This is the Claisen condensation.
The base removes an $\alpha$-hydrogen from one molecule of ethyl acetate to give a carbanion, $^-CH_2COOC_2H_5$.
The carbanion attacks the carbonyl carbon of a second molecule of ethyl acetate, and a molecule of ethanol is eliminated.
$CH_3-CO-OC_2H_5 + H-CH_2-CO-OC_2H_5 \xrightarrow{C_2H_5ONa} CH_3-CO-CH_2-CO-OC_2H_5 + C_2H_5OH$
The product is a $\beta$-keto ester, ethyl acetoacetate (ethyl 3-oxobutanoate), commonly called acetoacetic ester.
So the product is acetoacetic ester.
The base removes an $\alpha$-hydrogen from one molecule of ethyl acetate to give a carbanion, $^-CH_2COOC_2H_5$.
The carbanion attacks the carbonyl carbon of a second molecule of ethyl acetate, and a molecule of ethanol is eliminated.
$CH_3-CO-OC_2H_5 + H-CH_2-CO-OC_2H_5 \xrightarrow{C_2H_5ONa} CH_3-CO-CH_2-CO-OC_2H_5 + C_2H_5OH$
The product is a $\beta$-keto ester, ethyl acetoacetate (ethyl 3-oxobutanoate), commonly called acetoacetic ester.
So the product is acetoacetic ester.