A formylation reaction in organic chemistry is the catch-all name for any organic reaction in which an organic compound is functionalized with a formyl group (-CH=O).
Aromatic formylation reactions via electrophilic aromatic substitution include:
Dimethylformamide and phosphorus oxychloride in the Vilsmeier-Haack reaction
Hexamine in the Duff reaction and the Sommelet reaction
Carbon monoxide and hydrochloric acid in the Gattermann-Koch reaction
Anionic cyanides in the Gattermann reaction. This method synthetizes aromatic aldehydes using hydrogen chloride and hydrogen cyanide (or another metallic cyanide as such zinc cyanide) in the presence of Lewis acid catalysts:
Chloroform in the Reimer-Tiemann reaction
dichloromethyl methyl ether in Rieche formylation
Formylation of 3-methylamino-1-propanol with formamide (instead of ethyl chloroformate) as a protecting group in the preparation of Protriptyline. Formamide was also used (instead of formic acid) in the synthesis of primidone.
In biological systems, formylation is one of the processes of posttranslational modification in which a formyl group is added to the N-terminus of a protein.
