不对称的 [2 + 2] 烯酸交叉光添加在一个自组装的主体与远程利辅助器
Yuki Nishioka1, Takumi Yamaguchi, Masaki Kawano
1Department of Applied Chemistry, School of Engineering, The University of Tokyo, CREST, Japan Science and Technology Agency, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Journal of the American Chemical Society
|June 11, 2008
概括
在自组装的子中,远程性诱导在酸光添加中产生不对称的诱导. 这一发现提供了一种新的方法,用于创建具有高恩选择性的性分子.
科学领域:
- 超分子化学 超分子化学
- 摄影化学的使用.
- 有机合成 有机合成
背景情况:
- 在制药和材料科学中,奇拉性至关重要.
- 不对称的诱导是合成反反分子纯化合物的关键.
- 兰光添加是有机合成的一个发展领域.
研究的目的:
- 为了研究远程性对不对称诱导的影响.
- 为了探索氨酸的 [2+2] 交叉光添加.
- 开发一种新的方法来进行enantioselective合成.
主要方法:
- 自动组装的状子.
- 光化学 [2+2] 循环添加反应.
- 使用奇拉色谱 (chiral chromatography) 分析等离子体过量 (ee).
主要成果:
- 在子外围的远程性诱导了显著的不对称诱导.
- 在素光添加剂中,可以达到高达50%的反体过量 (ee).
- 这项研究证明了自组装子系统的有效性.
结论:
- 具有远程奇拉性的自组装子可以有效地控制立体化学.
- 这种方法为丰富衍生物提供了一条新的途径.
- 这些发现为设计新性催化剂和材料打开了道路.
相关概念视频
Cycloaddition Reactions: MO Requirements for Photochemical Activation
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.
Photochemical Electrocyclic Reactions: Stereochemistry
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
Cycloaddition Reactions: Overview
Cycloadditions are one of the most valuable and effective synthesis routes to form cyclic compounds. These are concerted pericyclic reactions between two unsaturated compounds resulting in a cyclic product with two new σ bonds formed at the expense of π bonds. The [4 + 2] cycloaddition, known as the Diels–Alder reaction, is the most common. The other example is a [2 + 2] cycloaddition.
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
The Diels–Alder reaction is an example of a thermal pericyclic reaction between a conjugated diene and an alkene or alkyne, commonly referred to as a dienophile. The reaction involves a concerted movement of six π electrons, four from the diene and two from the dienophile, forming an unsaturated six-membered ring. As a result, these reactions are classified as [4+2] cycloadditions.
Radical Anti-Markovnikov Addition to Alkenes: Overview
The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.
Cycloaddition Reactions: MO Requirements for Thermal Activation
Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.


