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.
Wu et al. (2026) studied this question.