An efficient preparation of acyl fluorides from carboxylic acids

?Acid fluorides, easily obtained from their corresponding carboxylic acids, present a unique balance between stability and reactivity. [1] Compared to acyl chlorides, acid fluorides are more stable to hydrolysis, and more reactive with amines. In the context of peptide synthesis, acid fluorides are less prone to racemization or to side reactions. [2] Schoenebeck et Coll. published an efficient and simple direct preparation of acid fluorides from carboxylic acids using (Me?N)SCF?, a bench-stable solid fluorinating reagent. [3] An example is reported in the Scheme below.

It should be pointed out that this procedure is base- and additive-free and presents a high functional group tolerance.

[1] For a recent review on this topic, see: J.-F. Paquin et al., Synthesis 2021, 53, 653-665.

[2] V. V. Sureshbabu et al., RSC Adv. 2015, 5, 48331-48362.

[3] F. Schoenebeck et al., Org. Lett. 2017, 19, 5740-5743.