Diethyl Malonate

Definition

Diethyl malonate is an organic compound with the formula CH2(COO-C2H5)2. It is a versatile building block in organic synthesis, commonly used in the alkylation of enolate ions as part of the Claisen condensation reaction.

5 Must Know Facts For Your Next Test

1. Diethyl malonate is a colorless, oily liquid that is widely used in organic synthesis as a \beta-ketoester precursor.
2. The two ethyl ester groups on diethyl malonate make it a reactive species that can undergo nucleophilic addition and substitution reactions.
3. In the context of 22.7 Alkylation of Enolate Ions, diethyl malonate is commonly used as an electrophile that can be alkylated by enolate ions.
4. The alkylation of diethyl malonate enolates is a key step in the synthesis of a variety of \beta-ketoester and \beta-hydroxyester compounds.
5. Diethyl malonate can also undergo decarboxylation reactions to form other useful synthetic intermediates, such as diethyl succinate.

Review Questions

• Explain the role of diethyl malonate in the Claisen condensation reaction.
  • In the Claisen condensation, diethyl malonate acts as one of the reactants, providing the \beta-ketoester functionality. The enolate ion of diethyl malonate undergoes nucleophilic addition to the carbonyl carbon of another ester or ketone, forming a new carbon-carbon bond and generating a \beta-ketoester product. This reaction is a powerful tool for the construction of more complex organic molecules from simpler starting materials.
• Describe how the alkylation of diethyl malonate enolates is used in organic synthesis.
  • The alkylation of diethyl malonate enolates is a versatile method for introducing substituents at the \alpha-carbon of the ester. By generating the enolate ion of diethyl malonate and then reacting it with an alkyl halide or other electrophile, a new carbon-carbon bond can be formed. This allows for the synthesis of a variety of \beta-ketoester and \beta-hydroxyester compounds, which are important intermediates in the preparation of more complex organic molecules. The alkylation reaction is a key step in many synthetic pathways and is widely used in organic chemistry.
• Analyze the factors that influence the reactivity and selectivity of diethyl malonate in alkylation reactions of enolate ions.
  • The reactivity and selectivity of diethyl malonate in alkylation reactions of enolate ions are influenced by several factors. The presence of the two electron-withdrawing ester groups increases the acidity of the \alpha-hydrogen atoms, facilitating enolate formation. The size and electronic properties of the alkyl halide electrophile can also affect the regioselectivity and stereochemistry of the alkylation. Additionally, the choice of base used to generate the enolate ion, as well as the reaction conditions (temperature, solvent, etc.), can all impact the outcome of the alkylation. Understanding these factors allows for the precise control and optimization of diethyl malonate alkylation reactions in organic synthesis.

Related terms

Enolate Ion: An enolate ion is a nucleophilic species derived from the enolization of a carbonyl compound, with the negative charge delocalized between the oxygen and \alpha-carbon atoms.

Claisen Condensation: The Claisen condensation is a carbon-carbon bond-forming reaction between the \alpha-carbon of an ester and the carbonyl carbon of another ester or ketone, forming a \beta-ketoester.

Alkylation: Alkylation is a chemical reaction that introduces an alkyl group (a group containing only carbon and hydrogen atoms) into a molecule.