Decarboxylations

Decarboxylation is a chemical reaction in which a carboxyl group is removed from an organic molecule as carbon dioxide. The process converts a substrate that bears a carboxyl group into a product lacking that group, with CO2 released in the course of the reaction. Decarboxylation can occur spontaneously under suitable structural conditions or be induced by heat, light, acids, bases, or catalysts.

In organic chemistry, decarboxylation is often driven by the presence of neighboring carbonyl groups or electron-withdrawing substituents. A classic example is the decarboxylation of beta-keto acids, which readily lose CO2 to form ketones. Malonic esters, upon hydrolysis and heating, undergo decarboxylation to yield substituted acetic acids, a key step in various synthetic sequences. Decarboxylation also features in decarboxylative coupling reactions, where carboxylate partners participate in forming new bonds with concurrent CO2 release.

In biochemistry, decarboxylation is a common enzymatic transformation. Amino acids can be decarboxylated by specific decarboxylase enzymes to form amines, releasing CO2 in the process. Metabolic decarboxylations are central to energy production and biosynthesis; for example, in the citric acid cycle, isocitrate and alpha-ketoglutarate are decarboxylated to release CO2, and pyruvate is decarboxylated to form acetyl-CoA with CO2 release.

Environmental and industrial aspects include the management of CO2 produced during decarboxylation steps in manufacturing and metabolism. While decarboxylation is often thermodynamically favorable when CO2 formation stabilizes the system, reaction conditions and catalysts are chosen to control rate, selectivity, and yield.