不对称的照片诱导激动状态纳扎罗夫反应
Xuelong Qiao1, Shaojun Zhai2, Jiwei Xu1
1Shanghai Key Laboratory of Green Chemistry and Chemical Processes, State Key Laboratory of Petroleum Molecular & Process Engineering, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China.
Journal of the American Chemical Society
|October 9, 2024
概括
这项研究引入了使用结催化反应的第一个不对称的光诱导激发状态纳扎罗夫反应. 化催化剂能够对二维尼尔基进行电循环,从而产生有价值的立体异构体.
科学领域:
- 有机化学
- 摄影化学
- 不对称的催化
背景情况:
- 纳扎罗夫循环是有机合成中的关键反应.
- 不对称的变种对于产生质纯化合物至关重要.
- 光诱导反应提供独特的反应途径.
研究的目的:
- 开发第一个非芳香双环乙烯基的非对称光诱导激发状态纳扎罗夫反应.
- 研究结催化在控制反选择性的作用.
- 探索这种新奇反应的合成实用性.
主要方法:
- 使用性结催化剂,特别是双功能混合尿素.
- 使用光解来启动激发状态的电循环.
- 进行机械学和密度函数理论 (DFT) 研究.
主要成果:
- 在二环维尼尔基的光诱导电循环过程中获得高反选择性.
- 证明催化剂结构和基质相互作用决定了选择性.
- 有良好的反选择性合成的三环.
结论:
- 开发的方法代表了不对称光化学的重大进步.
- 双功能催化剂通过键有效控制立体化学结果.
- 该反应具有温和的条件,广泛的范围和功能组耐受性,突出显示了其合成潜力.
相关概念视频
Photochemical Electrocyclic Reactions: Stereochemistry
1.8K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
1.8K
SN2 Reaction: Transition State
9.6K
An SN2 reaction of an alkyl halide is a single-step process in which bond formation between the nucleophile and the substrate and bond breaking between the substrate and the halide occurs simultaneously through a transition state without forming an intermediate.
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...
9.6K
Deactivation Processes: Jablonski Diagram
595
Luminescence, the emission of light by a substance that has absorbed energy, is a process that involves the interaction of molecules with light. The energy-level diagram, or Jablonski diagram, is a graphical representation of these interactions, illustrating the various states and transitions a molecule can undergo. In a typical Jablonski diagram, the lowest horizontal line represents the ground-state energy of the molecule, which is usually a singlet state. This state represents the energies...
595
Nucleophilic Aromatic Substitution: Addition–Elimination (SNAr)
3.8K
Nucleophilic substitution in aromatic compounds is feasible in substrates bearing strong electron-withdrawing substituents positioned ortho or para to the leaving group. The reaction proceeds via two steps: the addition of the nucleophile and the elimination of the leaving group.
The reaction begins with an attack of the nucleophile on the carbon that holds the leaving group. This results in the delocalization of the π electrons over the ring carbons. The resonance interaction between...
The reaction begins with an attack of the nucleophile on the carbon that holds the leaving group. This results in the delocalization of the π electrons over the ring carbons. The resonance interaction between...
3.8K
UV–Vis Spectroscopy: Molecular Electronic Transitions
1.4K
In Ultraviolet–Visible (UV–Vis) spectroscopy, the absorption of electromagnetic radiation is used to probe the electronic structure of molecules. This technique provides insights into molecular electronic transitions, particularly the movement of electrons between different molecular orbitals. Radiation is absorbed if the energy of the electromagnetic radiation passing through the molecule is precisely equal to the energy difference between the excited and ground states. During this...
1.4K
Cycloaddition Reactions: MO Requirements for Photochemical Activation
2.0K
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
2.0K


