甲基基的加法反应对CX双键
Yuman Hordijk1, Bart Waaijer1, Christopher B Kelly2
1Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute for Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam De Boelelaan 1108, Amsterdam 1081 HZ, The Netherlands.
The Journal of organic chemistry
|July 21, 2025
概括
对π系的基添加显示了周期表中可预测的趋势. 保利排斥显著影响激素反应性和区域选择性,为合成化学提供了新的见解.
科学领域:
- 有机化学 有机化学
- 计算化学计算化学
- 物理化学 物理化学
背景情况:
- 极端添加对于形成碳-碳和碳-异原子键至关重要.
- 了解反应性的周期性趋势对于设计新的合成途径至关重要.
研究的目的:
- 通过使用DFT.系统地调查对各种π-系统的甲基添加.
- 阐明反应障碍,能量和区域选择性的周期性趋势.
主要方法:
- 密度函数理论 (DFT) 计算使用ZORA-(U) OLYP/TZ2P.
- 在H2CX中的替代物X在14,15,和16组的系统变化.
- 轨道相互作用和保利排斥的分析.
主要成果:
- 在碳的添加障碍物减少,而在X的障碍物增加,从烯到烯.
- 反应能量在一段时间内变得不那么有利,但在一组内变得更有利.
- 区域选择性有利于在X的加法,除了CH2,NH和O,其中碳攻击占主导地位.
结论:
- 确定了甲基激素添加反应的明显周期性趋势.
- 保利排斥是一种关键的,经常被忽视的,影响激素反应性和区域选择性的因素.
- 这些发现为预测和控制 π 系统中激素加法反应提供了宝贵的见解.
相关概念视频
Radical Formation: Addition
1.8K
Radicals can be formed by adding a radical to a spin-paired molecule. This is typically observed with unsaturated species, where the addition of a radical across the π bond leads to the production of a new radical by dissolving the π bond. For example, the addition of a Br radical to an alkene yields a carbon-centered radical.
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an...
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an...
1.8K
Radical Reactivity: Electrophilic Radicals
2.0K
Radicals adjacent to electron‐withdrawing groups are called electrophilic radicals. These radicals readily react with nucleophilic alkenes. For example, the malonate radical, in which the radical center is flanked by two electron‐withdrawing groups, reacts readily with butyl vinyl ether, which consists of an electron‐donating oxygen substituent. The reaction between electrophilic malonate radical and nucleophilic vinyl ether is favored because the radical has a...
2.0K
Radical Anti-Markovnikov Addition to Alkenes: Mechanism
4.0K
The reaction of hydrogen bromide with alkenes in the presence of hydroperoxides or peroxides proceeds via anti-Markovnikov addition. The radical chain reaction comprises initiation, propagation, and termination steps.
The mechanism starts with chain initiation, which involves two steps. In the first chain initiation step, a weak peroxide bond is homolytically cleaved upon mild heating to form two alkoxy radicals. In the second initiation step, a hydrogen atom is abstracted by the alkoxy...
The mechanism starts with chain initiation, which involves two steps. In the first chain initiation step, a weak peroxide bond is homolytically cleaved upon mild heating to form two alkoxy radicals. In the second initiation step, a hydrogen atom is abstracted by the alkoxy...
4.0K
Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
2.8K
Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.
2.8K
Radical Substitution: Halogenation of Alkanes and Alkyl Substituents
8.5K
In the presence of heat or light, alkanes react with molecular halogens to form alkyl halides by a substitution reaction called radical halogenation. This reaction has three steps: initiation, propagation, and termination, as seen in the radical chlorination of methane to produce methyl chloride.
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
8.5K
Radical Anti-Markovnikov Addition to Alkenes: Overview
3.6K
The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.
3.6K


