thiolesterification

Thiolesterification is a chemical reaction that forms a thiolester bond. A thiolester is a functional group in organic chemistry with the general structure R-C(=O)-S-R', where R and R' are organic substituents. This linkage is analogous to an ester linkage, where the oxygen atom is replaced by a sulfur atom. The formation of a thiolester typically involves the reaction between a carboxylic acid and a thiol, or a reactive derivative of a carboxylic acid such as an acid halide or anhydride, with a thiol.

One common method for thiolesterification is the reaction of a carboxylic acid with a thiol in the presence of a coupling agent. These agents activate the carboxylic acid, making it more susceptible to nucleophilic attack by the thiol. Alternatively, the reaction can proceed via an activated carboxylic acid derivative. For example, an acid chloride can react directly with a thiol, often in the presence of a base to neutralize the hydrochloric acid byproduct.

Thiolester bonds are important in biological systems, notably in metabolism. Acetyl-CoA, a crucial molecule in cellular respiration, contains a thiolester bond. This bond is highly reactive and serves as a key energy currency, readily transferring its acyl group to other molecules. The biosynthesis and breakdown of fatty acids also involve thiolester intermediates. In synthetic organic chemistry, thiolesterification is employed to create molecules with specific functional group arrangements, often as intermediates in the synthesis of more complex compounds. The reactivity of the thiolester linkage can be exploited for further chemical transformations.