The initiation of diethyl malonate
begins with diethyl malonate, which is a commonly used starting material in organic synthesis. It has unique chemical properties and plays a key role in many reaction pathways.

Starting with diethyl malonate, the methylene of diethyl malonate can be deprotonated by the action of a base to form a stable carbon negative ion. This carbon negative ion has good activity and can undergo nucleophilic substitution reaction with halogenated hydrocarbons. In case of halogenated alkanes, according to the SN ² mechanism, the carbon negative ions attack the alpha-carbon of the halogenated alkane, and the halogen leaves to obtain alkyl-substituted diethyl malonate. This reaction has good selectivity and can introduce different alkyl structures by means of different halogenated hydrocarbons.

Then, through hydrolysis and decarboxylation steps, the alkyl-substituted diethyl malonate can be converted into the corresponding carboxylic acid. During hydrolysis, the ester group is hydrolyzed to a carboxyl group under acidic or basic conditions. After basic hydrolysis, it is acidified to obtain an intermediate product containing two carboxyl groups. After thermal decarboxylation, the carboxyl group is removed in the form of carbon dioxide, and the final target carboxylic acid is obtained.

In addition, diethyl malonate can also participate in the Knoevenagel condensation reaction. Under the catalysis of weak bases, it condenses with aldose or ketone to form α, β-unsaturated compounds. This reaction not only builds carbon-carbon double bonds, but also the product is an important intermediate in organic synthesis, which can be further added, cyclized and other reactions to construct complex organic molecular structures. The series of reactions starting with diethyl malonate provide rich strategies for organic synthesis and play an important role in the construction of molecular frameworks of various organic compounds.