Pd-Catalyzed Decarboxylative Negishi Coupling of Zinc Aryl Carboxylates with Arylthianthrenium Salts.

We report a Pd-catalyzed decarboxylative Negishi coupling reaction for efficient biaryl synthesis from various zinc aryl carboxylates, including polyfluorobenzoates and heteroaryl carboxylates, using DMF as the solvent. This mild reaction exhibits a broad substrate scope and enables late-stage functionalization of bioactive molecules. Mechanistic studies show that DMF-assisted zinc catalyzes decarboxylation of polyfluorinated aryl carboxylates to generate arylzinc reagents in situ, which then undergo Negishi coupling catalyzed by palladium with arylthianthrenium salts to form biaryl compounds. Notably, this protocol represents a rare example of zinc-mediated decarboxylation and demonstrates a novel strategy for preparing arylzinc reagents from easily accessible (hetero)aryl carboxylic acids.