Palladium-Catalyzed Ligand-Free Decarboxylative Coupling of α- Oxocarboxylic Acid with Aryl Diazonium Tetrafluoroborate: An Access to Unsymmetrical Diaryl Ketones.

Diaryl ketones are of much importance in organic synthesis as versatile intermediates and in industry for their useful properties. A mild and efficient palladium-catalyzed traditional ligand-free decarboxylative coupling of aryl α-keto carboxylic acid with aryl diazonium fluoroborate has been developed. A series of unsymmetrical diaryl ketones has been synthesized in moderate to good yields using this procedure. A radical pathway involving the acyl radical has been suggested.