Base-Free Suzuki–Miyaura Cross-Coupling Reaction Mediated by Lewis Acids

The palladium-catalyzed Suzuki–Miyaura cross-coupling (SMC) reaction of organohalides and organoborons is a reliable carbon–carbon bond-forming method. This reaction involves a base-mediated transmetalation process, but the presence of a base also promotes competitive protodeborylation, which reduces the efficiency. Herein, we established a base-free SMC reaction via Lewis acid-mediated transmetalation of an organopalladium(II) intermediate with organoborons. Experimental and theoretical investigations indicate that the controlled release of the transmetalation-active intermediate enabled base-free transmetalation under heating conditions and enhanced the applicable scope of this process. This system enabled us to avoid the use of a base, and thus, rendered substrates with base-sensitive moieties available.