asymmetric conjugate addition (ACA) of diethylzinc to various (E)-alkenyl aryl ketones where the aryl ring is either a phenyl group substituted by nitro, chloro or methoxy groups or not substituted, or a naphthyl group. When the conjugate addition was performed in the greener AcOEt solvent with 1 or 2 mol % of Cu(OTf)2/DiPPAM complex, moderate to good yields (45–83%) and high enantioselectivities (up to 98%)
2-Amino-1-phenyl-1,3-propanediol Derivatives. New Ligands for Asymmetric 1,4-Addition of Organozinc Reagents to Enones
作者:Tamotsu Fujisawa、Satoru Itoh、Makoto Shimizu
DOI:10.1246/cl.1994.1777
日期:1994.10
In the presence of (1S,2S)-3-benzyloxy-2-morpholino-1-phenylpropanol derived readily from (1S,2S)-2-amino-1-phenyl-1,3-propanediol and nickel acetylacetonate, diethylzinc added to α,β-unsaturated ketones to give alkylated product in high optical purity (up to 95%ee). The effects of solvents and additives and the use of such ligands as a chiral catalyst were also investigated.
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.
Construction of a new type of chiral bidentate NHC ligands: copper-catalyzed asymmetric conjugate alkylation
作者:Tatsuya Uchida、Tsutomu Katsuki
DOI:10.1016/j.tetlet.2009.06.026
日期:2009.8
We synthesized in three steps simple chiral bidentate NHC Compounds that carry an achiral coordinating group as N-substituent and revealed that they serve as efficient chiral auxiliaries for the copper-catalyzed asymmetric conjugate addition of dialkylzinc to acyclic enones (up to 97% ee). (C) 2009 Elsevier Ltd. All rights reserved.