Perfluoroalkylated Main‐Group Element Lewis Acids as Catalysts in Transfer Hydrogenation

Transfer hydrogenation plays an important part in organic chemistry. Recently, strong Lewis acids like B(C6F5)3 have been introduced as a catalyst for these reactions. We successfully employed the Lewis acid (C2F5)3PF2 as a catalyst in the transfer hydrogenation between 1,3,5‐trimethylcyclohexa‐1,4‐diene and 1,1‐diphenylethylene. Surprisingly, the treatment of the diene alone with a catalytic amount of (C2F5)3PF2 led to a quantitative dismutation to mesitylene and 1,3,5‐trimethylcyclohexane. With B(C6F5)3, there was a solvent‐dependency: in CH2Cl2 mainly the dismutation products were obtained, while in toluene the evolution of H2 was observed. Additionally, the catalytic activity of various perfluoroalkylated germanes and silanes was tested. The Lewis acid (C2F5)3PF2 catalyzes the transfer hydrogenation between 1,3,5‐trimethylcyclohexa‐1,4‐diene and 1,1‐diphenylethylene. Surprisingly, the treatment of the diene alone with a catalytic amount of (C2F5)3PF2 leads to a quantitative dismutation to mesitylene and 1,3,5‐trimethylcyclohexane. Additionally, the catalytic activity of various perfluoroalkylated germanes and silanes was tested.