In a Claisen reaction, two esters or an ester and a carbonyl compound react in the presence of a strong base to form a beta-keto ester or a beta-dicarbonyl compound. When an ester undergoes this reaction, it essentially forms a new carbon-carbon bond by deprotonating the alpha hydrogen of one ester and attacking the carbonyl carbon of another.
To specifically identify the beta-keto ester formed, we’d need to know the ester involved in the reaction. However, as a general rule, if you take an ester such as ethyl acetate and react it with a base like sodium ethoxide, you would form a beta-keto ester called 3-oxobutanoate. The general structure of the product will consist of a ketone group at the beta position relative to the ester functional group.
The mechanism involves the formation of an alkoxide ion from the ester, which then performs nucleophilic attack on the carbonyl carbon of another ester molecule, leading to the rearrangement and dehydration to yield the final beta-keto ester product. This transformation is significant in organic synthesis as it allows for the construction of complex molecules from simpler precursors.