Mild and Robust Redox-Neutral Pd/C-Catalyzed Lignol β-O-4' Bond Cleavage Through a Low-Energy-Barrier Pathway.
A Pd/C catalyzed redox neutral C¢O bond cleavage of 2-aryloxy-1-arylethanols has been developed. The reactions are carried out at 80 °C, in air, using a green solvent system to yield the aryl ketones in near quantitative yields. Addition of catalytic amounts of a hydrogen source to the reaction mixture activates the catalyst to proceed through a low energy barrier pathway. Initial studies support a transfer hydrogenolysis reaction mechanism that proceeds through an initial dehydrogenation followed by an enol adsorption to Pd/C and a reductive C¢O bond cleavage.
Department of Chemistry, BMC, Uppsala University, Husargatan 3, 751 23, Uppsala (Sweden).
Maxim V
MV
Galkin
Department of Chemistry, BMC, Uppsala University, Husargatan 3, 751 23, Uppsala (Sweden).
Christian
C
Dahlstrand
Department of Chemistry, BMC, Uppsala University, Husargatan 3, 751 23, Uppsala (Sweden). joseph.samec@kemi.uu.se.
Joseph S M
JS
Samec
D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D004987:Ethers / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry; D008031:Lignin / Q000737:chemistry; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*
D004987:Ethers; D007659:Ketones; D010165:Palladium; D002244:Carbon; D008031:Lignin
heterogeneous catalysis; lignin; palladium; reaction mechanisms; transfer hydrogenolysis