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Chapter 20

Radical Chemistry

自由基:电子结构和几何
自由基:电子结构和几何
This lesson delves into the geometry of a radical, which is influenced by the electronic structure of the molecule. The principle is similar to that of a ...
电子顺磁共振 (EPR) 波谱:有机自由基
电子顺磁共振 (EPR) 波谱:有机自由基
Ideally, an unpaired electron shows a single peak in the EPR spectrum due to the transition between the two spin energy states. However, coupling ...
自由基形成:概述
自由基形成:概述
A bond can be broken either by heterolytic bond cleavage to form ions or homolytic bond cleavage to yield radicals. A fishhook arrow is used to ...
自由基形成:均溶
自由基形成:均溶
A bond is formed between two atoms by sharing two electrons. When this bond is broken by supplying sufficient energy, either two electrons can be taken up ...
Radical Formation: Abstraction
Radical Formation: Abstraction
The electron of an atom can be abstracted from a compound by a relatively unstable radical to generate a new radical of relatively greater stability. For ...
自由基形成:加法
自由基形成:加法
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 ...
自由基形成:消除
自由基形成:消除
Another method of radical formation is the elimination process. It is the opposite of the addition route and is driven by the instability of the radical. ...
自由基反应性:概述
自由基反应性:概述
Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in ...
自由基反应性:空间位阻效应
自由基反应性:空间位阻效应
The presence of electron-donating, electron-withdrawing, or conjugating groups adjacent to a radical center, imparts electronic stabilization to the ...
自由基反应性:浓度效应
自由基反应性:浓度效应
In a radical reaction, the concentration of starting materials governs the selectivity of a radical. For example, the reaction between an alkyl halide and ...
自由基反应性:亲电自由基
自由基反应性:亲电自由基
Radicals adjacent to electron‐withdrawing groups are called electrophilic radicals. These radicals readily react with nucleophilic alkenes. For ...
自由基反应性:亲核自由基
自由基反应性:亲核自由基
Radicals adjacent to electron-donating groups are called nucleophilic radicals. These radicals readily react with electrophilic alkenes. The ...
自由基反应性:分子内与分子间
自由基反应性:分子内与分子间
Radical reactions can occur either intermolecularly or intramolecularly. In an intermolecular radical reaction, a nucleophilic radical adds to an ...
自由基自氧化
自由基自氧化
The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form ...
烯丙基和苄基醇的自由基氧化
烯丙基和苄基醇的自由基氧化
Activated manganese(IV) oxide can selectively oxidize allylic and benzylic alcohols via a radical intermediate mechanism. Primary allylic alcohols are ...
自由基取代:烷烃和烷基取代基的卤化
自由基取代:烷烃和烷基取代基的卤化
In the presence of heat or light, alkanes react with molecular halogens to form alkyl halides by a substitution reaction called radical halogenation. This ...
自由基卤化:热力学
自由基卤化:热力学
The thermodynamic favorability of a reaction is determined by the change in Gibbs free energy (ΔG). ΔG has two components- enthalpy (ΔH) ...
自由基卤化:立体化学
自由基卤化:立体化学
Stereochemistry is the study of the different spatial arrangements of atoms in a given molecule. The stereochemistry of radical halogenations can be ...
自由基取代:烯丙基氯化
自由基取代:烯丙基氯化
Typically, when alkenes react with halogens at low temperatures, an addition reaction occurs. However, upon increasing the temperature or under reaction ...
自由基取代:烯丙基溴化
自由基取代:烯丙基溴化
In organic synthesis, the formation of products can be altered by changing the reaction conditions. For example, a dibromo addition product is ...
自由基取代:烷基卤化物与三丁基锡氢化物的氢解
自由基取代:烷基卤化物与三丁基锡氢化物的氢解
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the ...
对 Alkenes 的激进反马尔科夫尼科夫添加:概述
对 Alkenes 的激进反马尔科夫尼科夫添加:概述
The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl ...
烯烃的激进反马尔科夫尼科夫加成:机制
烯烃的激进反马尔科夫尼科夫加成:机制
The reaction of hydrogen bromide with alkenes in the presence of hydroperoxides or peroxides proceeds via anti-Markovnikov addition. The radical chain ...
烯烃的自由基反马尔科夫尼科夫加成:热力学
烯烃的自由基反马尔科夫尼科夫加成:热力学
The anti-Markovnikov addition of hydrogen halides to an alkene is thermodynamically feasible only with HBr. The radical addition reaction with other ...
通过醛或酮的还原偶联产生邻接二醇:频哪醇偶联概述
通过醛或酮的还原偶联产生邻接二醇:频哪醇偶联概述
Wilhelm Rudolph Fittig discovered the pinacol coupling reaction in 1859. It is a radical dimerization reaction and involves the reductive coupling of ...
烯烃通过醛或酮的还原偶联:McMurry 反应
烯烃通过醛或酮的还原偶联:McMurry 反应
The radical dimerization of ketones or aldehydes gives vicinal diols through a pinacol coupling reaction. However, the behavior of titanium metals used ...
通过酯的还原偶联得到 α-羟基酮:Acyloin 缩合概述
通过酯的还原偶联得到 α-羟基酮:Acyloin 缩合概述
The pinacol and McMurry reactions involve the reductive coupling of ketones or aldehydes. Similarly, the bimolecular reductive coupling of two ester ...
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