Benzene (and other arenes) react with formyl fluoride in the presence of boron trifluoride to give benzaldehyde. In a related reaction, formyl chloride is implicated in Gattermann-Koch formylation reaction.
Benzene (and related aromatic compounds) combine with formyl fluoride and boron trifluoride to produce benzaldehyde. Analogously, formyl chloride is also utilized in the Gattermann-Koch formylation reaction.