Formylation reaction

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 formylations exist with:
 * dimethylformamide and phosphorus oxychloride in the Vilsmeier-Haack reaction
 * hexamine in the Duff reaction
 * carbon monoxide and hydrochloric acid in the Gattermann-Koch reaction
 * zinc cyanide and hydrochloric acid in the Gatterman Aldehyde Synthesis
 * chloroform in the Reimer-Tiemann reaction

These reactions are all electrophilic aromatic substitutions