不对称的转移化与双功能铁化物:实验满足计算
Lorena De Luca1, Alessandro Passera1, Antonio Mezzetti1
1Department of Chemistry and Applied Biosciences , ETH Zurich , Zurich 8093 , Switzerland.
Journal of the American Chemical Society
|January 10, 2019
概括
奇拉铁化合物 (5) 催化了不对称的化. 它由铁氧化物前体形成,并由于其独特的宏环结构和异酸连接体而达到高反选择性.
科学领域:
- 有机金属化学
- 不对称的催化
- 铁复合物
背景情况:
- 在过渡金属催化中,奇拉N2P2宏循环是有效的配体.
- 铁复合物越来越多地被研究为贵金属催化剂的可持续替代品.
- 不对称转移化 (ATH) 对于合成性分子至关重要.
研究的目的:
- 通过使用奇拉铁复合体在子的不对称转移化中识别催化活性物种.
- 阐明反应机制,并了解控制酶选择性的因素.
- 描述新的铁和氧化物复合物.
主要方法:
- 铁复合物的合成和表征.
- 测试反应路径的固体测量反应.
- 核磁共振 (NMR) 光谱用于结构分析.
- 密度功能理论 (DFT) 计算用于机械洞察和结构阐明.
主要成果:
- 催化活性物种是一种性铁化物复合物,cis-β-[FeH ((CNCEt3) ((1))) BF4 (5).
- 复合物5是通过从铁2-复合物 (8a) 中的H消除而形成的.
- 铁化物插入了乙烯基的碳基,从而产生异体醇复合物 (10R和10S).
- DFT计算支持使用铁氧化物作为静止状态的双功能机制.
- 一个立体化学模型准确地预测了乙芬的高反选择性.
结论:
- 奇拉铁化合物 (5) 是一种高效的非对称转移化催化剂.
- 刚性宏循环连接体和庞大的异基连接体的组合决定了高的反选择性.
- 这项研究为铁催化不对称化反应提供了有价值的机理见解.
相关概念视频
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.9K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.9K
Hydrogen Bonds
133.1K
Hydrogen bonds are weak attractions between atoms that have formed other chemical bonds. One of these atoms is electronegative, like oxygen, and has a partial negative charge. The other is a hydrogen atom that has bonded with another electronegative atom and has a partial positive charge.
Hydrogen Bonds Control the World!
Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are unequally shared....
Hydrogen Bonds Control the World!
Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are unequally shared....
133.1K
Hydrogen Bonds
14.1K
A hydrogen bond is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) is attracted to another electronegative atom from another polar molecule, such as water (H2O), hydrogen fluoride (HF), or ammonia (NH3). The huge electronegativity difference between the H atom (2.1) and the atom to which it is bonded (4.0 for an F atom, 3.5 for an O atom, or 3.0 for an N atom), combined with the very small size of an H atom...
14.1K
Esters to Alcohols: Hydride Reductions
4.8K
Esters are reduced to primary alcohols when treated with a strong reducing agent like lithium aluminum hydride. The reaction requires two equivalents of the reducing agent and proceeds via an aldehyde intermediate.
Lithium aluminum hydride is a source of hydride ions and functions as a nucleophile. The mechanism proceeds in three steps. Firstly, the nucleophilic hydride ion attacks the carbonyl carbon of the ester to form a tetrahedral intermediate. Subsequently, the carbonyl group re-forms,...
Lithium aluminum hydride is a source of hydride ions and functions as a nucleophile. The mechanism proceeds in three steps. Firstly, the nucleophilic hydride ion attacks the carbonyl carbon of the ester to form a tetrahedral intermediate. Subsequently, the carbonyl group re-forms,...
4.8K
Rotation of Asymmetric Top
1.5K
By definition, a spherically symmetric body has the same moment of inertia about any axis passing through its center of mass. This situation changes if there is no spherical symmetry. Since most rigid bodies are not spherically symmetric, these require special treatment.
The relationship between the angular momentum of any rigid body and its angular velocity, both of which are vectors, involves the moment of inertia. The moment of inertia is a scalar quantity only for spherically symmetric...
The relationship between the angular momentum of any rigid body and its angular velocity, both of which are vectors, involves the moment of inertia. The moment of inertia is a scalar quantity only for spherically symmetric...
1.5K
Asymmetric Lipid Bilayer
9.8K
Biological membranes show uneven distribution of different types of lipids in the inner and outer layers, resulting in transverse asymmetric membranes. The treatment of the erythrocyte membrane with the enzyme phospholipase confirmed the asymmetric nature of the lipid bilayer. The enzyme hydrolyzes lipids into fatty acids and hydrophilic groups. The phospholipase acts only on the outer layer of the membrane, while the inner layer remains intact. The phospholipase treatment resulted in 80%...
9.8K


