Phosphirenium Ions as Masked Phosphenium Catalysts: Mechanistic Evaluation and Application in Synthesis
Danila Gasperini, Samuel E. Neale, Mary F. Mahon, Stuart A. Macgregor, Ruth L. Webster
Abstract
bond addition over the C=O group, and associative displacement of the product by a further equivalent of the carbonyl substrate, which completes the catalytic cycle. A competing off-cycle process leading to vinyl phosphine formation is detailed for the hydrosilylation of benzophenone for which an inverse order in [silane] is observed. Experimentally, the formation of side products, including off-cycle vinyl phosphine, is favored by electron-donating substituents on the phosphirenium cation, while catalytic hydrosilylation is promoted by electron-withdrawing substituents. These observations are rationalized in parallel computational studies.
Topics & Concepts
ChemistryHydrosilylationCatalysisNucleophileBenzophenoneCatalytic cyclePhotochemistryPhosphineSilanesFuranSilaneOrganic chemistryOrganoboron and organosilicon chemistrySynthesis and characterization of novel inorganic/organometallic compoundsSynthetic Organic Chemistry Methods