This study introduces a new class of phenylpyridine-based borenium salts as highly efficient Lewis acid catalysts for carbon–carbon bond formation. The authors demonstrate that these cationic boron species enable the homocoupling of diaryldiazomethanes to form tetraarylethylenes under remarkably mild conditions and with very low catalyst loadings. Compared to conventional neutral boron Lewis acids, the borenium catalysts show superior performance, highlighting the importance of their cationic character and steric properties. Mechanistic and computational studies reveal a pathway involving substrate activation, nitrogen extrusion, and carbocation intermediates. Overall, the work expands the scope of main-group catalysis and provides a promising alternative to transition-metal-based methods for C–C bond construction.
More information in the article: https://pubs.acs.org/doi/10.1021/acs.inorgchem.5c04965