A Zinc Catalyzed C(sp3)−C(sp2) Suzuki–Miyaura Cross‐Coupling Reaction Mediated by Aryl‐Zincates

The Suzuki–Miyaura (SM) reaction is one of the most important methods for C−C bond formation in chemical synthesis. In this communication, we show for the first time that the low toxicity, inexpensive element zinc is able to catalyze SM reactions. The cross‐coupling of benzyl bromides with aryl borates is catalyzed by ZnBr2, in a process that is free from added ligand, and is compatible with a range of functionalized benzyl bromides and arylboronic acid pinacol esters. Initial mechanistic investigations indicate that the selective in situ formation of triaryl zincates is crucial to promote selective cross‐coupling reactivity, which is facilitated by employing an arylborate of optimal nucleophilicity. Old dog, new metal: The cross coupling of benzyl bromides with aryl borates is catalyzed by ZnBr2, in a process that is compatible with a range of functionalized benzyl bromides and arylboronic acid pinacol esters. Mechanistic investigations indicate that the in situ formation of triaryl zincates is crucial to promote selective cross‐coupling reactivity.