Nickel-Catalyzed Acylation of Aryl Bromides with Acyl Imidazoles

Alkyl imidazolides were herein found to be viable coupling partners for the Ni-catalyzed acylation of aryl bromides. This cross-coupling reaction features a broad substrate scope and be performed in an extremely cost-efficient fashion. Mechanistically, formation of acyl radicals via reduction of imidazolides represents a major departure from other reported radical acylation reactions. Of particular note, extensive studies revealed an intriguing radical chain mechanism and a remarkable CO-extrusion-recombination phenomenon. Finally, the practicality of this cross-coupling was demonstrated with a gram-scale reaction for the synthesis of a furan diterpenoid natural product.