Electro/Ni Dual-Catalyzed Decarboxylative C(sp3)−C(sp2) Cross-Coupling Reactions of Carboxylates and Aryl Bromide

Paired redox-neutral electrolysis offers an attractive green platform for organic synthesis by avoiding sacrificial oxidants and reductants. Here, we report the electro/Ni dual-catalyzed redox-neutral C(sp3)−C(sp2) cross-coupling reactions between carboxylates and aryl bromides. At a cathode, an NiII(Ar)(Br) intermediate is formed through the activation of the Ar−Br bond by a NiI-bipyridine catalyst and subsequent one electron reduction. The carboxylates, including amino acid, benzyl carboxylic acid, and 2-phenoxy propionic acid, undergo oxidative decarboxylation at an anode to form carbon based radicals. The combination of the NiII(Ar)(Br) intermediate and the carbon radical results in the formation of C(sp3)−C(sp2) cross-coupling products. The broad reaction scope, excellent functional group tolerance, and good yields of the electro/Ni dual-catalyzed C(sp3)−C(sp2) cross-coupling reaction were confirmed through 48 examples of carboxylates and aryl bromides in small-scale vial reactions and scale-up flow synthesis. The electro/Ni dual-catalyzed cross-coupling reactions described in this study are expected to have broad applications in the construction of C(sp3)−C(sp2) bonds because of the readily available carboxylate nucleophiles and the scalability of electrochemical flow-synthesis technology.