Selective Hydrogenation of Heteroarenes Using Supported Ruthenium Phosphide Nanoparticle Catalysts

The selective hydrogenation of heteroarenes, including quinolines, indoles, benzofurans, and benzothiophenes, to the corresponding aromatic compounds is enabled by ruthenium phosphide nanoparticles on imidazolium-based supported ionic liquid phases, Ru_<i>x</i>P_100-<i>x</i>@SILP, as catalysts. The organometallic approach to the synthesis and immobilization of ruthenium phosphide nanoparticles (NPs) allows preparation under mild wet-chemistry conditions and systematic variation of the Ru/P ratio. The novel materials are characterized using various techniques, including electron microscopy and X-ray spectroscopies, and are found to be highly active, selective, and robust for application under batch and continuous flow conditions. The synthetic potential of Ru₅₀P₅₀@SILP as the most promising catalyst is demonstrated for a wide variety of substrates, enabling the synthesis of valuable drug molecules (e.g., cuspareine and salsolidine) and providing access to useful synthons including isotope labeling for fine chemicals and pharmaceuticals.