title: Palladium-Catalyzed Hydrolytic Cleavage of Aromatic C-O Bonds.
abstract: Metallic palladium surfaces are highly selective in promoting the reductive hydrolysis of aromatic ethers in aqueous phase at relatively mild temperatures and pressures of H2. At quantitative conversions, the selectivity to hydrolysis products of PhOR ethers was observed to range from 50 % (R=Ph) to greater than 90 % (R=n-C4H9, cyclohexyl, and PhCH2CH2). By analysis of the evolution of products with and without incorporation of H218O, the pathway was concluded to be initiated by palladium metal catalyzed partial hydrogenation of the phenyl group to an enol ether. Water then rapidly adds to the enol ether to form a hemiacetal, which then undergoes elimination to cyclohexanone and phenol/alkanol products. A remarkable feature of the reaction is that the stronger Ph-O bond is cleaved rather than the weaker aliphatic O-R bond.
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99352, USA.
authors.forename: Meng
authors.identifier: 0000-0002-3380-3534
authors.initials: M
authors.lastname: Wang
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99352, USA.
authors.forename: Hui
authors.identifier: 0000-0003-1180-7443
authors.initials: H
authors.lastname: Shi
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99352, USA.
authors.forename: Donald M
authors.identifier: 0000-0002-2213-0960
authors.initials: DM
authors.lastname: Camaioni
authors.affiliation: Institute for Integrated Catalysis, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99352, USA.|Department of Chemistry and Catalysis Research Institute, TU München, Lichtenbergstrasse 4, 85748, Garching, Germany.
authors.forename: Johannes A
authors.identifier: 0000-0002-2495-1404
authors.initials: JA
authors.lastname: Lercher
keywords: aryl ethers; hydrogenation; palladium; reductive hydrolysis; selective cleavage