Palladium-Catalyzed Direct Annulation of Benzoic Acids with Phenols to Synthesize Dibenzopyranones

Direct annulation of benzoic acids with phenols via palladium-catalyzed oxidative coupling is reported. Readily available and inexpensive starting materials were used in this novel method to synthesize highly valuable and useful dibenzopyranone scaffolds. Broad substrate scope and simple operation make this method potentially practical. Preliminary mechanistic studies were conducted to understand this chemistry and inspire new designs of oxidative coupling of different functionalized arenes.