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Nickel-mediated hydrogenolysis of C-O bonds of aryl ethers: what is the source of the hydrogen?

ABSTRACT: Mechanistic studies of the hydrogenolysis of aryl ethers by nickel were undertaken with (diphosphine)aryl methyl ethers. A Ni(0) complex containing Ni-arene interactions adjacent to the aryl-O bond was isolated. Heating led to aryl-O bond activation and generation of a nickel aryl methoxide complex. Formal ?-H elimination from this species produced a nickel aryl hydride which can undergo reductive elimination in the presence of formaldehyde to generate a carbon monoxide adduct of Ni(0). The reported complexes map out a plausible mechanism of aryl ether hydrogenolysis catalyzed by nickel. Investigations of a previously reported catalytic system using isotopically labeled substrates are consistent with the mechanism proposed in the stoichiometric system, involving ?-H elimination from a nickel alkoxide rather than cleavage of the Ni-O bond by H(2).

SUBMITTER: Kelley P

PROVIDER: S-EPMC3340012 | biostudies-other | 2012 Mar

REPOSITORIES: biostudies-other

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Nickel-mediated hydrogenolysis of C-O bonds of aryl ethers: what is the source of the hydrogen?

Kelley Paul P Lin Sibo S Edouard Guy G Day Michael W MW Agapie Theodor T

Journal of the American Chemical Society 20120313 12

Mechanistic studies of the hydrogenolysis of aryl ethers by nickel were undertaken with (diphosphine)aryl methyl ethers. A Ni(0) complex containing Ni-arene interactions adjacent to the aryl-O bond was isolated. Heating led to aryl-O bond activation and generation of a nickel aryl methoxide complex. Formal β-H elimination from this species produced a nickel aryl hydride which can undergo reductive elimination in the presence of formaldehyde to generate a carbon monoxide adduct of Ni(0). The repo ...[more]

PMID: 22394331

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