Belli, RomanMuir, VanessaDyck, NicholasPantazis, Dimitrios A.Sousa, Tânia P. A.Slusar, Carly R.Parkin, HayleyRosenberg, Lisa2024-05-242024-05-242024Belli, R. G., Muir, V., Dyck, N. B., Pantazis, D. A., Sousa, T. P. A., Slusar, C. R., Parkin, H. C., & Rosenberg, L. (2024). Exploring electrophilic hydrophosphination via metal phosphenium intermediates. Chemistry, 30(16). https://doi.org/10.1002/chem.202302924https://doi.org/10.1002/chem.202302924https://hdl.handle.net/1828/16554Two Mo(0) phosphenium complexes containing ancillary secondary phosphine ligands have been investigated with respect to their ability to participate in electrophilic addition at unsaturated substrates and subsequent P−H hydride transfer to “quench” the resulting carbocations. These studies provide stoichiometric “proof of concept” for a proposed new metal-catalyzed electrophilic hydrophosphination mechanism. The more strongly Lewis acidic phosphenium complex, [Mo(CO)4(PR2H)(PR2)]+ (R=Ph, Tolp), cleanly hydrophosphinates 1,1-diphenylethylene, benzophenone, and ethylene, while other substrates react rapidly to give products resulting from competing electrophilic processes. A less Lewis acidic complex, [Mo(CO)3(PR2H)2(PR2)]+, generally reacts more slowly but participates in clean hydrophosphination of a wider range of unsaturated substrates, including styrene, indene, 1-hexene, and cyclohexanone, in addition to 1,1-diphenylethylene, benzophenone, and ethylene. Mechanistic studies are described, including stoichiometric control reactions and computational and kinetic analyses, which probe whether the observed P−H addition actually does occur by the proposed electrophilic mechanism, and whether hydridic P−H transfer in this system is intra- or intermolecular. Preliminary reactivity studies indicate challenges that must be addressed to exploit these promising results in catalysis.enAttribution 4.0 InternationalArticleDepartment of Chemistry