Palladium-Catalyzed Carbonylation of Aryl Chlorides to Electrophilic Aroyl-DMAP Salts

The palladium-catalyzed carbonylative coupling of aryl chlorides and 4-dimethylaminopyridine (DMAP) to generate electrophilic aroyl-DMAP salts is described. In contrast to classical carbonylation reactions, which often require nucleophiles to react with weakly electrophilic palladium-acyl intermediates, the high electrophilicity of aroyl-DMAP salts allows the acylation of a broad range of substrates. This transformation is mediated by a palladium-Xantphos catalyst, and mechanistic studies suggest the combination of ligand steric strain together with Pd(0) stabilization allows both the reductive elimination of a reactive ArCO-DMAP product and oxidative addition of the strong aryl-chloride bond. Overall, this transformation allows the generation of amides and esters from aryl chlorides with an array of nucleophiles and with good functional group compatibility.