具有高度反选择性的非对称的-曼尼克反应,由具有多个键的双功能氨酸-尿素载体多个键供体催化
Chun-Jiang Wang1, Xiu-Qin Dong, Zhi-Hai Zhang
1College of Chemistry and Molecular Sciences, Wuhan University, P.R. China. cjwang@whu.edu.cn
Journal of the American Chemical Society
|June 14, 2008
概括
奇拉氨基-尿酸催化高度选择性的尼特罗-曼尼克反应. 多个结捐赠体提高反应速率,产量和立体化学控制.
科学领域:
- 有机化学 有机化学
- 不对称的催化剂.
背景情况:
- -曼尼克反应是一个关键的碳-碳键形成反应.
- 在这些反应中实现高立体选择性仍然是一个挑战.
研究的目的:
- 开发一种新型的催化系统,用于高度抗选择性和抗选择性-曼尼克反应.
- 调查多个结捐赠体在催化中的作用.
主要方法:
- 使用了性双功能氨基尿酸催化剂.
- 选了各种基质用于尼特罗-曼尼克反应.
- 分析了反应产品的产量, diastereoselectivity 和 enantioselectivity.
主要成果:
- 对广泛的基质实现了高的抗选择性和酶选择性.
- 证明了多个结捐赠体在加速反应中的重要作用.
- 由于多个结捐赠体,观察到提高了产量,二选择性和选择性.
结论:
- 奇拉双功能氨基-尿酸是立体选择性-曼尼克反应的有效催化剂.
- 多个结相互作用对于优化催化性能至关重要.
相关概念视频
Electrophilic Aromatic Substitution: Nitration of Benzene
The nitration of benzene is an example of an electrophilic aromatic substitution reaction. It involves the formation of a very powerful electrophile, the nitronium ion, which is linear in shape. The reaction occurs through the interaction of two strong acids, sulfuric and nitric acid.
Preparation of Amines: Reductive Amination of Aldehydes and Ketones
Carbonyl compounds and primary amines undergo reductive amination first to produce imines, followed by secondary amines in the same reaction mixture, using selective reducing agents like sodium cyanoborohydride or sodium triacetoxyborohydride. Reductive amination produces different degrees of substitution of amines depending on the starting amine substrate.
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
Acid Halides to Amides: Aminolysis
Aminolysis is a nucleophilic acyl substitution reaction, where ammonia or amines act as nucleophiles to give the substitution product. Acid halides react with ammonia, primary amines, and secondary amines to yield primary, secondary, and tertiary amides, respectively.
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
Nitriles to Amines: LiAlH4 Reduction
Nitriles are reduced to amines in the presence of strong reducing agents like lithium aluminum hydride through a typical nucleophilic acyl substitution. The reaction requires two equivalents of the reducing agent. The reducing agent acts as a source of hydride ions.
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
Preparation of 1° Amines: Azide Synthesis
Direct alkylation of ammonia produces polyalkylated amines, along with a quaternary ammonium salt. To exclusively prepare primary amines, the azide synthesis method can be used.
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...
Azide ions act as good nucleophiles and react with unhindered alkyl halides to form alkyl azides. Alkyl azides do not participate in further nucleophilic substitution reactions, thereby eliminating the chances of polyalkylated products. Alkyl azides are reduced by hydride-based reducing agents, like lithium aluminum...


