The Critical Role of Reductive Steps in the Nickel-Catalyzed Hydrogenolysis and Hydrolysis of Aryl Ether C-O Bonds
Journal Article
·
· Angewandte Chemie International Edition
- BATTELLE (PACIFIC NW LAB)
- UNIVERSITY PROGRAMS
- TIANJIN UNIVERSITY
Hydrogenolysis of the aromatic C-O bond in aryl ethers is catalyzed by Ni in decalin or water at 150 °C. Observations of a significant kinetic isotope effect (kH/kD = 5.7) for the reactions of diphenyl ether under H2 and D2 and a positive dependence of the rate on H2 chemical potential in decalin indicate that addition of H to the aromatic ring is the rate-limiting step rather than C-O scission. Hydrogen addition occurs on the metal before C-O bond scission. DFT calculations indicate that hydrogen atom addition to the ortho position followed by C-O scission is energetically more feasible than C-O scission followed by H addition to either phenoxyl or phenyl moieties. Hydrogenolysis initiated via H addition in water is more selective (~75 %) compared to reactions in decalin (~30 %). The high selectivity for hydrogenolysis is attributed to stabilization of polar transition state by water as a polar solvent.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1614997
- Report Number(s):
- PNNL-SA-144365
- Journal Information:
- Angewandte Chemie International Edition, Journal Name: Angewandte Chemie International Edition Journal Issue: 4 Vol. 59
- Country of Publication:
- United States
- Language:
- English
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The Critical Role of Reductive Steps in the Nickel‐Catalyzed Hydrogenolysis and Hydrolysis of Aryl Ether C−O Bonds
Journal Article
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Wed Dec 11 19:00:00 EST 2019
· Angewandte Chemie
·
OSTI ID:1579369