Enantioselective Addition of Dialkylzinc to Aromatic Aldimines Mediated by Camphor-Derived Chiral β-Amino Alcohols
作者:Wei-Ming Huang、Biing-Jiun Uang
DOI:10.1002/asia.201403240
日期:2015.4
The enantioselective addition of diethylzinc or dimethylzinc to N‐(diphenylphosphinoyl)imines mediated by 1 or 2 could be achieved in high yields (70–97 %) and enantioselectivities (85–98 % ee). The catalytic loading of 1 or 2 a could be reduced to 10 mol % for methylation or ethylation of imines in high yields and enantioselectivities (79–96 %) when the reaction was conducted in the presence of 1
The present invention relates to a method of enantioselective addition to imines, including: reacting R
2
CH═NY with R
3
ZnR
4
in the presence of a compound represented by the following formula (I),
in which Y, R
1
, R
2
, R
3
and R
4
are defined the same as the specification. Accordingly, the present invention can prepare secondary amines in high yields and enantiomeric excess by the above-mentioned method.
Synthesis of novel well-defined chain-end-functionalized polystyrenes with dendritic chiral ephedrine moieties and their applications as highly enantioselective diethylzinc addition to N-diphenylphosphinoyl arylimines
作者:Ashraf A. El-Shehawy
DOI:10.1016/j.tet.2007.08.093
日期:2007.11
A series of novel well-defined chain-end-functionalized polystyrenes having 2, 4, 8, and 16 chiral ephedrine moietiesdendritically distributed at their hyperbranched chain-ends were quantitatively synthesized. Their well-defined architectures were fully confirmed by elemental analysis, FTIR, SEC as well as by 1H and 13C NMR spectroscopies. These polymers were precisely controlled in the molecular
定量合成了一系列新颖的,定义明确的,具有2、4、8和16个手性麻黄碱部分在其超支化链端分布的手性麻油碱部分的链端官能化聚苯乙烯。通过元素分析,FTIR,SEC以及1 H和13 C NMR光谱学充分证实了它们的明确定义的体系结构。这些聚合物的分子量和分子量分布均得到精确控制,链端官能团也得到了明确定义。这些树状手性聚合物在二乙基锌向一系列N的对映选择性加成中充当高度对映选择性的手性配体-二苯基膦酰基芳基丙氨酸。其中,在链末端具有八个麻黄碱部分的手性树枝状聚合物以高至高收率提供了对映异构体富集的膦酰基酰胺,其对映选择性高达93%ee。所获得的对映选择性与使用N-苄基麻黄碱及其相应的共聚物作为手性配体所获得的对映选择性相当。
Asymmetric, Catalytic Synthesis of α-Chiral Amines Using a Novel Bis(phosphine) Monoxide Chiral Ligand
作者:Alessandro A. Boezio、Julien Pytkowicz、Alexandre Côté、André B. Charette
DOI:10.1021/ja038291+
日期:2003.11.1
We have shown that Me-DuPHOS monoxide (BozPHOS) is a very effective ligand in the copper-catalyzed addition of dialkylzinc to N-phosphinoylimines providing access to alpha-chiral amines. The new ligand is particularly effective for the addition of the lesser reactive dimethylzinc. The major advantages of this process are high yields, broad substrate scope, and high enantioselectivities with low catalyst