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.
When benzene and other arenes react with formyl fluoride under the influence of boron trifluoride, they generate benzaldehyde. Similarly, in another reaction, formyl chloride plays a role in the Gattermann-Koch formylation procedure.