Department of Chemistry, University of California, Berkeley, Berkeley, California 94720-1460, United States.
J Am Chem Soc. 2012 Dec 19;134(50):20226-9. doi: 10.1021/ja3085912. Epub 2012 Dec 7.
A heterogeneous nickel catalyst for the selective hydrogenolysis of aryl ethers to arenes and alcohols generated without an added dative ligand is described. The catalyst is formed in situ from the well-defined soluble nickel precursor Ni(COD)(2) or Ni(CH(2)TMS)(2)(TMEDA) in the presence of a base additive, such as (t)BuONa. The catalyst selectively cleaves C(Ar)-O bonds in aryl ether models of lignin without hydrogenation of aromatic rings, and it operates at loadings down to 0.25 mol % at 1 bar of H(2) pressure. The selectivity of this catalyst for electronically varied aryl ethers differs from that of the homogeneous catalyst reported previously, implying that the two catalysts are distinct from each other.
一种用于芳基醚选择性氢解为芳烃和醇的非均相镍催化剂,无需外加配位配体即可生成。该催化剂是由可溶性镍前体 Ni(COD)(2)或 Ni(CH(2)TMS)(2)(TMEDA)在碱添加剂(如(t)BuONa)存在下原位形成的。该催化剂选择性地断裂木质素芳基醚模型中的 C(Ar)-O 键,而不会使芳环加氢,并且在 1 巴 H(2)压力下,其负载量低至 0.25mol%时仍能保持活性。与之前报道的均相催化剂相比,该催化剂对电子变化的芳基醚具有不同的选择性,这意味着两种催化剂彼此不同。