核友添加到1,2,3-三 1-氧化物中的位点逆转
Luca De Angelis1, Graham C Haug1, Gildardo Rivera2
1Department of Chemistry, The University of Texas at San Antonio, San Antonio, Texas 78249, United States.
Journal of the American Chemical Society
|June 9, 2023
概括
这项研究探讨了对1,2,3-triazines及其1-oxide衍生物的核性添加,区分反应场所. 它揭示了各种核友的区域选择性和反应条件,有助于合成化学.
科学领域:
- 有机化学
- 异环化学
- 合成方法
背景情况:
- 逆电子需求迪尔斯-阿尔德 (IEDDA) 循环添加是1,2,3-triazines的一个关键反应.
- 对1,2,3-triazines的核性添加是已知的,但缺乏对区域选择性的全面理解.
- 核性攻击的首选部位 (C-4与C-6) 仍未被探索.
研究的目的:
- 研究和区分1,2,3-triazine和1,2,3-triazine-1-oxide框架上的核友添加部位.
- 探索各种核友 (C-, N-, H-, O-, S-) 与这些异环系统的反应性.
- 阐明这些反应中影响区域选择性的因素.
主要方法:
- 合成不对称的1,2,3--1-氧化物及其无氧化对应物.
- 这些三氧化物系统与多种核友的反应,包括碳素,氨基,化物,氧化物和硫醇.
- 使用计算研究来分析反应机制,区域选择性以及硬体和电子因素的影响.
主要成果:
- 在酸和酸-1氧化物系统中,C和N核友好物优先添加到C-6位置,在酸-1氧化物中观察到更快的产物形成.
- O核友 (氧化物) 对三-1-氧化物的C-4位置具有很高的选择性.
- 在温和的功能组耐受性条件下,S核友和化物表现出明显的区域选择性,在某些情况下,C-6对三和C-4对三-1-氧化物产生添加.
结论:
- 这项工作提供了对1,2,3-triazine和1,2,3-triazine-1-oxide支架的核友添加区域选择性的全面了解.
- 这项研究强调了基于核友和三氧化状态的反应场所的区分能力.
- 这些发现为涉及1,2,3-衍生物的合成策略的合理设计提供了宝贵的见解.
相关概念视频
Nucleophilic Aromatic Substitution of Aryldiazonium Salts: Aromatic SN1
2.1K
Treating arylamines with nitrous acid gives aryldiazonium salts that are effective substrates in nucleophilic aromatic substitution reactions. The diazonio group in these salts can be easily displaced by different nucleophiles, yielding a wide variety of substituted benzenes. The leaving group departs as nitrogen gas, and this easy elimination is the driving force for the substitution reaction.
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo,...
In the Sandmeyer reaction, for example, the diazonio group is replaced by a chloro, bromo,...
2.1K
Nucleophilic Aromatic Substitution: Elimination–Addition
4.0K
Simple aryl halides do not react with nucleophiles. However, nucleophilic aromatic substitutions can be forced under certain conditions, such as high temperatures or strong bases. The mechanism of substitution under such conditions involves the highly unstable and reactive benzyne intermediate. Benzyne contains equivalent carbon centers at both ends of the triple bond, each of which is equally susceptible to nucleophilic attack. This 50–50 distribution of products is...
4.0K
Nucleophilic Aromatic Substitution: Addition–Elimination (SNAr)
3.9K
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...
3.9K
Diazonium Group Substitution: –OH and –H
2.8K
Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.
2.8K
SN1 Reaction: Stereochemistry
8.7K
This lesson provides an in-depth discussion of the stereochemical outcomes in an SN1 reaction.
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...
8.7K
SN1 Reaction: Mechanism
12.1K
Kinetic studies of ionization of a tertiary halide in a protic solvent suggest that only the substrate participates in the rate-determining step (slow step). The nucleophile is involved only after the slowest step. The SN1 reaction takes place in a multiple-step mechanism.
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a...
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a...
12.1K


![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)