[Concept]
In the presence of a strong base such as sodium alcohol, the hydrogen atoms on the active methylene acetate are replaced with compounds containing active halogen atoms to form a substituted b-ketoate, which is then decomposed by keto or acid to form a reaction of keto or acid, called ethyl acetate synthesis.
[Example]
Ethyl monosubstitution and di-substitution acetoacetate are similar to ethyl acetoacetate and can also be ketone-type decomposition (dilute base) or acid decomposition (concentrated base), so it can be used to synthesize one-substituted and two-substituted acetone or one-substituted and two-substituted acetic acid.
[Reaction Mechanism of Substitution]
[Mechanism of keto decomposition]
[Mechanism of acid decomposition]
[Issues to be aware of in response]
In the synthesis reaction, the groups introduced are: (1) alkyl groups, introduced with haloalkanes. Generally speaking, the primary halal alkane yield is higher, and there are more olefin by-products when using secondary haloalkanes, while tertiary haloalkanes are mainly eliminated by olefins. The reaction rate is 1. >2。 When two different hydrocarbon groups are introduced, it is generally the first group with a relatively large molecular mass. Ethylene halogenates and aromatic halogen compounds are generally not available. (2) Keto group, introduced with halogenated ketones. (3) Carboxylate groups, introduced with halocarboxylates.
The synthesis of ethyl acetate is widely used in organic synthesis, and is often used in the synthesis of methyl ketones, binary ketones, ketoacids and cyclic compounds.
[Reaction example]