Silane Redistribution Catalyzed by [Mes-B-TMP]⁺ Borinium Ion.

Borinium ions, featuring two empty p orbitals at boron, exhibit exceptional Lewis acidity but often suffer from excessive reactivity that limits their catalytic utility. In this study, we demonstrate that the arylamino borinium ion [1]⁺ effectively mediates aryl transfer in ArMe₂SiH to afford Ar₂SiMe₂ and Me₂SiH₂ under mild conditions. The reaction can also be extended to cross-coupling between ArMe₂SiH and Et₂SiH₂/Et₃SiH. Computational studies revealed that the amino substituent in [1]⁺ plays a pivotal role in modulating the Lewis acidity of the boron center, enabling reversible Si-H activation while preventing irreversible B-C bond cleavage and catalyst decomposition. These findings highlight the potential of electronically tuned borinium ions as catalysts for activating inert substrates in organic transformations.