Highly Enantioselective Conjugate Addition of Diethylzinc to Acyclic Enones with Fine-Tunable Phosphite−Pyridine Ligands
作者:Huihui Wan、Yuanchun Hu、Yuxue Liang、Shuang Gao、Junwei Wang、Zhuo Zheng、Xinquan Hu
DOI:10.1021/jo0345897
日期:2003.10.1
and (S)-2-amino-2'-hydroxy-4,4',6,6'-tetramethyl-1,1'-biphenyl was employed in Cu(I)-catalyzed conjugate addition of diethylzinc to acyclicenones. Excellent enantioselectivities (up to 98% ee) and highly catalytic activities were achieved for a variety of acyclicenones.
The present invention relates to a method of enantioselective addition to enones, including: reacting R
3
(CH
2
)
p
CH═CR
5
C(═O)Y(CH
2
)
q
R
4
with R
6
ZnR
7
in the presence of a compound represented by the following formula (I) and a transition metal catalyst,
in which Y, p, q, R
1
, R
2
, R
3
, R
4
, R
5
, R
6
and R
7
are defined the same as the specification. Accordingly, the present invention can perform asymmetric conjugate addition in high yields and enantioselectivity.
Highly enantioselective 1,4-conjugate addition of diethylzinc to acyclic enones with chiral phosphite–pyridine ligands derived from H8-NOBIN
作者:Yuanchun Hu、Xinmiao Liang、Junwei Wang、Zhuo Zheng、Xinquan Hu
DOI:10.1016/j.tetasy.2003.09.020
日期:2003.12
A series of new phosphite-pyridine ligands, based on the H-8-binaphthyl backbone, were synthesized and employed in the copper-catalyzed enantioselective 1,4-conjugate addition of diethylzinc to acyclic enones. Ligands derived from (S)-H-8-NOBIN provided better results than their parent ligands in the reaction. Ligand L1 provided excellent ees for trans -4-aryl-3-buten-2-ones (up to 97.8% ee) as substrates. Ligand L2 was very efficient for various para-chalcones, and up to 97.2% ee was achieved. (C) 2003 Elsevier Ltd. All rights reserved.
Development of New Chiral P,N Ligands and Their Application in the Cu-Catalyzed Enantioselective Conjugate Addition of Diethylzinc to Enones
High enantioselectivity (up to 98 % ee) has been achieved for the conjugate addition of diethylzinc to acyclic enones utilizing Cu(I) complexes of the novel chiral P,N ligands 1. The high enantioselectivities are best achieved using [Cu(OTf)](2) small middle dotC(6)H(6) as the copper catalyst precursor in nonpolar solvents such as toluene or Cl(CH(2))(2)Cl. R=H, CH(3); Tf=F(3)CSO(2).
Readily Prepared Chiral P,N Ligands and Their Applications in Cu-Catalyzed Enantioselective Conjugate Additions
作者:Yuanchun Hu、Xinmiao Liang、Junwei Wang、Zhuo Zheng、Xinquan Hu
DOI:10.1021/jo0340758
日期:2003.5.1
A new type of phosphite-pyridine (P,N) ligand derived from (S)-NOBIN and (S)-BINOL was employed in Cu(I)-catalyzed conjugate addition of diethylzinc to chalcones. The new P,N ligands were highly efficient in the copper-catalyzed enantioselective 1,4-conjugate additions of diethylzinc to acyclic enones, and up to 97% ee was achieved.