Simple and easily accessible chiral lithium amide salts are reported as efficient (pre)catalysts for the diastereo‐ [up to (E:Z)=92:8] and enantioselective [up to 72% ee (E)] hydroamination/cyclisation of conjugated primary aminodienes. These chiral lithium salts are straightforwardly prepared by in situ combination of an N‐substituted (R)‐(+)‐1,1′‐binaphthyl‐2,2′‐diamine ligand and a commercial methyllithium
Synthesis, structure, and catalytic activity of chiral silver(I) and copper(II) complexes with biaryl-based nitrogen-containing ligands
作者:Haiyan Zhang、Liang Chen、Haibin Song、Guofu Zi
DOI:10.1016/j.ica.2010.11.023
日期:2011.1
two-coordinated Ag(I) complexes. Reaction of AgX with 1 equiv of chiral N4-ligands 5, 7, 8 and 10 gives the chiral, binuclear double helicate Ag(I) complexes, while chiral mono-nuclear single helicate Ag(I) complexes are obtained with N4-ligands 6 and 9. Treatment of either N3-ligand 1 or N4-ligand 9 or 10 with 1 equiv of CuX2 (X = Cl, ClO4) gives the mono-ligated Cu(II) complexes. All the complexes have been
Synthesis, Structure, and Catalytic Activity of Ti
<sup>IV</sup>
and Zr
<sup>IV</sup>
Complexes Derived from (
<i>R</i>
)‐2,2′‐Diamino‐1,1′‐binaphthyl‐Based N
<sub>4</sub>
‐Donor Ligands
作者:Li Xiang、Haibin Song、Guofu Zi
DOI:10.1002/ejic.200701105
日期:2008.3
reacts with Ti(NMe2)4 (1 equiv.) to give chiral titanium amide 1-Ti(NMe2)2·C6H6 (3·C6H6), whereas treatment of 2H2 with Ti(NMe2)4 (1 equiv.) leads to the isolation of bis(ligated) product (2)2-Ti·C7H8 (5·C7H8) in 74 % yield. All complexes were characterized by various spectroscopic techniques, elemental analysis, and X-ray diffraction analysis. Zirconium amides 4 and 6 are active catalysts for the asymmetric
(R)-N,N′-bis(pyridin-2-ylmethyl)-1,1′-binaphthyl-2,2′-diamine (2) in 95% yield. Rigidity plays an important role in the formation of helicatesilver(I) complexes. Treatment of 1, or 3 with 1 equiv of AgNO3 in mixed solvents of MeOH and CH2Cl2 (1:4) gives the chiral, dinuclear doublehelicate Ag(I) complexes [Ag2(1)2][NO3]2 (4) and [Ag2(3)2][NO3]2 · 2H2O (6), respectively, in good yields. While under the
Enantioselective Hydrogenation of Aromatic Ketones Catalyzed by Ru Complexes of Goodwin−Lions-type sp<sup>2</sup>N/sp<sup>3</sup>N Hybrid Ligands R-BINAN-R‘-Py
Goodwin-Lions-type sp2N/sp3N hybrid ligands R-BINAN-R'-Py possessing a C2 axis binaphthyl skeleton have been designed and synthesized. Combination of the new non-phosphine ligand with Ru(pi-CH2C(CH3)CH2)2(cod) has been revealed to catalyze the hydrogenation of aromatic ketones with high enantioselectivity of up to 99% ee. The reaction proceeds essentially without the need for any bases, but the reactivity is enhanced by the addition of KOt-C4H9 attaining an S/C ratio of up to 10 000. The success should expand the range of possibilities in designing catalysts not only for hydrogenation but also for many other reactions.