FriedelCraftsasyloinnissa

Friedel-Crafts acylation is an organic chemical reaction that attaches an acyl group to an aromatic ring. This process is a type of electrophilic aromatic substitution. The reaction typically involves an aromatic compound, an acyl halide or anhydride, and a Lewis acid catalyst. Common Lewis acids used include aluminum chloride (AlCl3), ferric chloride (FeCl3), or zinc chloride (ZnCl2).

The mechanism begins with the Lewis acid coordinating with the acyl halide or anhydride, generating a highly reactive acylium ion, which is a strong electrophile. This acylium ion then attacks the electron-rich aromatic ring. Following the initial attack, a sigma complex is formed, which is then deprotonated to restore aromaticity. The catalyst is regenerated in the process.

Friedel-Crafts acylation is a versatile method for introducing carbonyl groups into aromatic systems. The acyl group can then be further modified through various reactions, such as reduction to an alkyl group or oxidation. One key advantage of acylation over alkylation is that the acyl group is deactivating, preventing further substitution on the ring, which can be a problem with Friedel-Crafts alkylation. This reaction is widely used in the synthesis of pharmaceuticals, fragrances, and other fine chemicals. However, it is important to note that the reaction is not suitable for strongly deactivated aromatic rings.