Question

Formation of aceto-acetic-ester by the reaction of sodium ethoxide with ethyl acetate is called
A. trans-esterification
B. Tishchenko-reaction
C. saponification
D. Claisen condensation

Answer 1

Hint: Ethyl acetoacetate \[(C{{H}_{3}}COC{{H}_{2}}COO{{C}_{2}}{{H}_{5}})\], also called acetoacetic ester, an ester widely used as an intermediate in the synthesis of many varieties of organic chemical compounds. Industrially it is employed in the manufacture of synthetic drugs and dyes.

Complete step by step answer:
The solutionThe Claisen condensation reaction is an organic coupling reaction that results in the formation of a C-C bond between both a single ester and one carbonyl compound or between two esters. The reaction proceeds when a strong base is present and the product of the reaction is a beta-keto ester or a beta-diketone. The general reaction of the Claisen condensation reaction is given below.

Formation of aceto-acetic-ester by the reaction of sodium ethoxide with ethyl acetate is called Claisen-condensation. Ethyl alcohol is produced as by product.The reaction is given below;

\[ 2C{{H}_{3}}CO{{C}_{2}}{{H}_{5}}\xrightarrow[(ii){{H}_{3}}{{O}^{+}}]{(i){{C}_{2}}{{H}_{5}}ONa}C{{H}_{3}}COC{{H}_{2}}COO{{C}_{2}}{{H}_{5}}+{{C}_{2}}{{H}_{5}}OH\]

So, the correct answer is Option D.

Additional Information:
1.The Claisen condensation reaction requires that a minimum of one reagent must have an alpha proton and can form an enolate anion upon deprotonation.
2.The reaction also requires the base to avoid participating in nucleophilic substitution reactions or nucleophilic addition with a carbon belonging to the carbonyl functional group.
3.An ideal base for this reaction is the sodium alkoxide which is the conjugate base of the alcohol to be formed since it is regenerated

Note: The Claisen condensation reaction is closely related to the aldol condensation reaction since both of them are organic condensation reactions involving the addition of enolates to organic compounds. However, the aldol condensation reaction involves the addition of enolates to ketones or aldehydes whereas Claisen condensation involves the addition of enolates to esters.