Evolution of chiral Lewis basic N-formamide as highly effective organocatalyst for asymmetric reduction of both ketones and ketimines with an unprecedented substrate scope
作者:Li Zhou、Zhouyu Wang、Siyu Wei、Jian Sun
DOI:10.1039/b703307a
日期:——
L-Pipecolinic acid derived Lewis basic N-formamide has been developed as a first highly effective catalyst for the asymmetric reduction of aromatic and aliphatic ketones as well as aromatic and aliphatic ketimines in good to high enantioselectivity.
<i>S</i>-Chiral Sulfinamides as Highly Enantioselective Organocatalysts
作者:Dong Pei、Zhouyu Wang、Siyu Wei、Yu Zhang、Jian Sun
DOI:10.1021/ol062633+
日期:2006.12.1
accessible chiral sulfinamide 2 has been developed as the first highly efficient and enantioselectiveorganocatalyst relying solely on a chiral sulfur center for stereochemical induction. In the presence of 20 mol % of 2, a broad range of N-aryl ketimines 1 were reduced by trichlorosilane to produce amines 3 in high yield and enantioselectivity. [reaction: see text]
Formamides derived from N-methyl amino acids serve as new chiral organocatalysts in the enantioselective reduction of aromatic ketimines with trichlorosilane
作者:Andrei V. Malkov、Sigitas Stončius、Kenneth N. MacDougall、Andrea Mariani、Grant D. McGeoch、Pavel Kočovský
DOI:10.1016/j.tet.2005.08.117
日期:2006.1
Asymmetric reduction of N-aryl ketimines 1a–k, 43, and 45 with trichlorosilane can be catalyzed by new N-methyl l-amino acid-derived Lewis-basic organocatalysts, such as the valine-derived bisamide 3d (10 mol%), in toluene at room temperature with high enantioselectivity (≤92% ee). The structure–reactivity investigation shows that the product configuration is controlled by the nature of the side chain
N-芳基酮亚胺1a - k,43和45用三氯硅烷的不对称还原可以由新的N-甲基l-氨基酸衍生的Lewis碱性有机催化剂催化,例如缬氨酸衍生的双酰胺3d(10 mol%),在室温下在甲苯中具有高对映选择性(≤92%ee)。结构反应研究表明,产物构型受催化剂支架侧链性质的控制(例如,在3d和6e中,i -Pr vs Me)),因此相同绝对构型的催化剂可能会诱导产物相反的对映异构体的形成。催化剂与传入的亚胺之间的芳烃-芳烃相互作用似乎是不对称诱导的前提。这种无金属的有机催化方案与传统的金属催化方法相比具有竞争优势。
Role of Noncovalent Interactions in the Enantioselective Reduction of Aromatic Ketimines with Trichlorosilane
作者:Andrei V. Malkov、Andrea Mariani、Kenneth N. MacDougall、Pavel Kočovský
DOI:10.1021/ol049213+
日期:2004.6.1
[reaction: see text] Asymmetric reduction of ketimines 1 with trichlorosilane can be catalyzed by a new N-methyl L-valine derived Lewis basic organocatalyst, such as 4d, with high enantioselectivity. The structure-reactivity investigation suggests hydrogen bonding and arene-arene interactions between the catalyst and the incoming imine as the main factor determining the enantiofacial selectivity.
Chiral Dienes as “Ligands” for Borane-Catalyzed Metal-Free Asymmetric Hydrogenation of Imines
作者:Yongbing Liu、Haifeng Du
DOI:10.1021/ja4025808
日期:2013.5.8
This paper describes a highly enantioselective metal-free hydrogenation of imines using chiral dienes as "ligands" for the generation of catalysts with HB(C6F5)2 by hydroboration in situ to furnish a variety of chiral amines with up to 89% ee, which provides a practical strategy for the development of novel chiralfrustratedLewispairs for asymmetric hydrogenation.
本文描述了使用手性二烯作为“配体”对亚胺进行高度对映选择性的无金属氢化,通过原位硼氢化反应生成具有 HB(C6F5)2 的催化剂,以提供各种手性胺,其 ee 高达 89%,从而提供开发用于不对称氢化的新型手性受阻路易斯对的实用策略。