acylgruppen

Acylgruppen, or acyl groups, are a class of functional groups in organic chemistry with the general structure R–CO–, where R represents an substituent such as an alkyl or aryl group. The acyl group is derived from carboxylic acids by removing the hydroxyl group, leaving a carbonyl carbon double-bonded to oxygen and single-bonded to R. The acyl fragment can act as a substituent in a wide range of compounds.

Commonly, acyl groups are named as alkanoyl or by use of familiar names such as formyl, acetyl, or benzoyl. For example, the formyl group is H–CO–, the acetyl group is CH3–CO–, and the benzoyl group is C6H5–CO–. In many contexts the term acyl is used to distinguish the carbonyl-containing fragment from the rest of the molecule, and it is distinct from the purely carbonyl (C=O) unit.

In chemical reactions, the acyl group is highly electrophilic at the carbonyl carbon, which enables nucleophilic acyl substitution. This leads to the formation of esters (R–CO–OR′), amides (R–CO–NR′2), and anhydrides (R–CO–O–CO–R′). Acyl chlorides (R–CO–Cl) and anhydrides are common acylating agents, where the leaving group (Cl or OR′) drives the reaction. The reactivity and selectivity of acyl transfer depend on the nature of the leaving group and the surrounding substituents.

Applications of acyl groups include protecting group strategies in synthesis (for example, acetyl or benzoyl protections) and biochemical roles such as acyl-CoA thioesters in metabolism.