Mechanistic Understanding of the Heterogeneous, Rhodium-Cyclic (Alkyl)(Amino)Carbene-Catalyzed (Fluoro-)Arene Hydrogenation
Daniel Moock, Mario P. Wiesenfeldt, Matthias Freitag, Satoshi Muratsugu, Satoru Ikemoto, Robert Knitsch, Jacob Schneidewind, Wolfgang Baumann, Andreas Schäfer, Alexander Timmer, Mizuki Tada, Michael Ryan Hansen, Frank Glorius
Abstract
Recently, chemoselective methods for the hydrogenation of fluorinated, silylated, and borylated arenes have been developed providing direct access to previously unattainable, valuable products. Herein, a comprehensive study on the employed rhodium-cyclic (alkyl)(amino)carbene (CAAC) catalyst precursor is disclosed. Mechanistic experiments, kinetic studies, and surface-spectroscopic methods revealed supported rhodium(0) nanoparticles (NP) as the active catalytic species. Further studies suggest that CAAC-derived modifiers play a key role in determining the chemoselectivity of the hydrogenation of fluorinated arenes, thus offering an avenue for further tuning of the catalytic properties.