Acylation

Definition

Acylation is a chemical reaction in which an acyl group (such as an acetyl or benzoyl group) is introduced into a molecule, typically by the reaction of a carboxylic acid or its derivative with another compound. This process is central to the preparation of carboxylic acids, nucleophilic acyl substitution reactions, the chemistry of thioesters and acyl phosphates, and the reactions of amines.

5 Must Know Facts For Your Next Test

1. Acylation is a fundamental reaction in organic chemistry that introduces an acyl group into a molecule, often through the reaction of a carboxylic acid or its derivative with another compound.
2. In the preparation of carboxylic acids, acylation is used to convert alcohols or alkenes into carboxylic acids via reactions such as the Baeyer-Villiger oxidation.
3. Nucleophilic acyl substitution reactions involve the attack of a nucleophile on the carbonyl carbon of a carboxylic acid derivative, leading to the formation of a new acyl-containing product.
4. Thioesters and acyl phosphates are important biological carboxylic acid derivatives that participate in acylation reactions, playing crucial roles in energy transfer and biosynthetic pathways.
5. The reactions of amines, such as the acylation of amines to form amides, are also examples of acylation processes that are widely used in organic synthesis and biochemistry.

Review Questions

• Explain the role of acylation in the preparation of carboxylic acids, as described in Section 20.5.
  • Acylation is a key step in the preparation of carboxylic acids from alcohols or alkenes. For example, in the Baeyer-Villiger oxidation, an acyl group is introduced to an alcohol or ketone, which is then further oxidized to form a carboxylic acid. This acylation reaction is crucial for the conversion of simpler organic compounds into more complex carboxylic acid products.
• Describe how acylation is involved in nucleophilic acyl substitution reactions, as discussed in Section 21.2.
  • Nucleophilic acyl substitution reactions involve the attack of a nucleophile on the carbonyl carbon of a carboxylic acid derivative, such as an acyl chloride or anhydride. This acylation step replaces the leaving group with the nucleophile, forming a new acyl-containing product. The ability of carboxylic acid derivatives to undergo acylation reactions is central to their reactivity in these substitution processes.
• Discuss the importance of acylation in the chemistry of thioesters and acyl phosphates, as outlined in Section 21.8, and how it relates to biological carboxylic acid derivatives.
  • Thioesters and acyl phosphates are crucial biological carboxylic acid derivatives that participate in acylation reactions. Thioesters, which contain a sulfur atom bonded to the acyl group, are involved in energy transfer and biosynthetic pathways. Acyl phosphates, on the other hand, are high-energy intermediates that facilitate the transfer of acyl groups in various metabolic processes. The ability of these compounds to undergo acylation reactions is fundamental to their roles as acyl group carriers in the complex biochemical reactions that sustain life.

Related terms

Acyl Group: An acyl group is a functional group with the general formula R-C(=O)-, where R is an alkyl or aryl group. It is derived from a carboxylic acid by the removal of a hydroxyl group.

Nucleophilic Acyl Substitution: A type of reaction where a nucleophile attacks the carbonyl carbon of a carboxylic acid derivative, replacing the leaving group and forming a new acyl-containing product.

Thioester: A thioester is a functional group with the structure R-C(=O)-S-R', where the sulfur atom is bonded to an alkyl or aryl group. Thioesters are important in biological systems as acyl group carriers.