Decarboxylative Cross-Coupling of Acyl Fluorides with Potassium Perfluorobenzoates

Abstract

We report the transition metal-free decarboxylative cross-coupling reactions of acyl fluorides with potassium perfluorobenzoates. Compared with traditional transition metal-catalyzed cross-couplings, this protocol presents an extremely environmentally benign pathway to afford unsymmetrical diaryl ketones. To install perfluorophenyl groups, this method highlights highly selective, inexpensive, and nontoxic conditions. The reaction system tolerates various functional groups in acyl fluorides. Remarkably, all of the starting materials can be prepared from abundant carboxylic acids and the reaction proceeds without any catalysts and additives.

Phosphine‐Catalyzed Acyl‐Group Exchange Reaction of Carboxylic Acids and an Aroyl Fluoride

“…As mentioned later, one of the roles of PCy 3 should be a base, that produces a carboxylate anion from a carboxylic acid. Thus, when a control experiment using sodium benzoate ( 40 ) and acyl fluoride 2 was performed in the absence of PCy 3 , three acid anhydrides 41 – 43 and benzoyl fluoride ( 7 ) were detected (Scheme 6C) [28] . Then, to check the backward reaction of the acyl‐group exchange reaction, 2,6‐difluorobenzoic acid ( 4 ) and 3,5‐dimethylbenzoyl fluoride ( 3 ) were treated with a catalytic amount of PCy 3 in NMP at 80 °C for 20 h (Scheme 6D).…”

Recent Advances in C–F Bond Activation of Acyl Fluorides Directed toward Catalytic Transformation by Transition Metals, N-Heterocyclic Carbenes, or Phosphines

“…In 2020, a base-promoted decarboxylative coupling reaction of acyl fluorides with polyfluorobenzoates was developed by our group. 101 In this reaction system, polyfluorobenzoates play an unprecedented role in the synthesis of a series of unsymmetrical ketones with broad functional-group tolerance under extremely practical and environmentally benign conditions (Scheme 53). In this reaction, acyl fluoride reacts with polyfluorobenzoate to form the mixed anhydride A, from which three possible pathways are proposed.…”