Direct Fluoroformylation of the C3-Position of Indoles with 2,4-Dinitro(trifluoromethoxy)benzene as Fluorocarbonyl Source.

We herein report the direct fluoroformylation of indoles and other heteroaromatic cycles. Acyl fluorides are very useful moieties in coupling reactions with or without metal. However, they are usually obtained from the corresponding carboxylic acids or from aryl halides in pallado-catalyzed carbonylation/fluorination reactions. Our method uses fluorophosgene generated in situ from 2,4-dinitro(trifluoromethoxy)benzene (DNTFB) as a fluoroformylating agent without any metal and from carboxylic acid-free heteroaromatic rings. Moreover, our method can be telescoped with amidification reactions in a one-pot process.