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Synfacts 2016; 12(4): 0421
DOI: 10.1055/s-0035-1561798
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart · New York

Hydrogenolysis of Diaryl Ether C–O Bonds Using a Nickel/Carbon Catalyst

Contributor(s):
Yasuhiro Uozumi
,
Yoichi M. A. Yamada
,
Rikako Ishii
Gao F, Webb JD, Hartwig JF * University of California, Berkeley, USA
Chemo- and Regioselective Hydrogenolysis of Diaryl Ether C–O Bonds by a Robust Heterogeneous Ni/C Catalyst: Applications to the Cleavage of Complex Lignin-Related Fragments.

Angew. Chem. Int. Ed. 2016;
55: 1474-1478
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Further Information

Publication History

Publication Date:
15 March 2016 (online)

 
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Key words

hydrogenolysis - ethers - nickel catalysis - bond cleavage - regioselectivity

Significance

The hydrogenolysis of compounds that mimic the diaryl ether moieties in lignin was catalyzed by nickel nanoparticles on carbon (Ni/C) in the presence of sodium tert-butoxide or potassium hexamethyldisilazide under hydrogen to give the corresponding arenes in >98% yield and high selectivity. The hydrogenolysis of ether 1 with Ni/C took place without significant aggregation of nickel particles [2–5 nm (1 h); 5–7 nm (24 h)].


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Comment

[Ni(cod)2] (10 mol%) catalyzed the hydrogenolysis of ether 1 at 180 °C for 24 hours with 20% conversion; during this period, the nickel particles aggregated from a size of 4–13 nm (1 h) to 17–23 nm (24 h), as observed by TEM. The authors previously reported that hydrogenolysis of 1 occurred in 45% conversion yield with a ligand-free nickel catalyst at 120 °C for 48 h (Science 2011, 332, 439).


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