Concept explainers
Interpretation:
Given that the third and fourth steps in the synthesis of Hagemann’s ester from ethyl acetoacetate are intramolecular aldol cyclization to yield a substituted cyclohexenone and a decarboxylation reaction. Both reactions are to be shown and products of each step are to be shown.
Concept introduction:
In intramolecular aldol reactions dicarbonyl compounds such as diketones react with a base to yield a cyclic enone as the products. The reaction occurs in three steps i) Abstraction of α-hydrogen by a base to yield an enolate anion ii) Attack of the anion on the carbonyl carbon in the same molecule iii) Protonation of the alkoxide intermediate.
A β-ketoacid normally eliminates CO2 on heating.
To show:
The third and fourth steps in the synthesis of Hagemann’s ester from ethyl acetoacetate, the intramolecular aldol cyclization to yield a substituted cyclohexenone and a decarboxylation reaction and further to show the products of these reactions.
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Chapter 23 Solutions
Organic Chemistry
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