A Fortuitous, Mild Catalytic Carbon–Carbon Bond Hydrogenolysis by a Phosphine-Free Catalyst

The putative catalyst trans-[Ru((S,S)-skewphos)(H)2((R,R)-dpen)] (skewphos = 2,4-bis(diphenylphosphino)pentane; dpen = 1,2-diphenylethylenediamine) transforms the trifluoroacetyl amide 2,2,2-trifluoro-1-(piperidin-1-yl)ethanone under mild conditions (4 atm H2, room temperature, 4–24 h, 1 mol-% Ru, 15 mol-% KOtBu in tetrahydrofuran) to generate the formylated amine 1-formylpiperidine and fluoroform via C–C bond hydrogenolysis. Catalysts are also prepared by reacting cis-[Ru(η3-C3H5)(MeCN)2(COD)]BF4 (COD = 1,5-cyclooctadiene) with diamine ligands in situ. Low-temperature NMR studies provided insight into this reaction.