催化三元化 bis-silylated diazomethane 的催化三元化
Muhammad Farooq Ibad1, Peter Langer, Fabian Reiß
1Abteilung Anorganische Chemie, Institut für Chemie, Universität Rostock, Albert-Einstein-Straße 3a, D-18059 Rostock, Germany.
Journal of the American Chemical Society
|September 25, 2012
概括
以三甲基基替代的二甲经过催化异构和三构,形成一种新型的pyrazole衍生物. 本研究详细介绍了使用DFT计算的反应机制,动力学和热力学.
科学领域:
- 有机化学 有机化学
- 含有的异环环,含有的异环.
- 反应机制研究研究反应机制研究.
背景情况:
- 双三甲基二甲 ((Me(3) Si) (((2) CNN) 是一种具有复杂化学转化潜力的前体.
- 催化在指导化二甲衍生物的反应性方面发挥着至关重要的作用.
研究的目的:
- 为了研究 (Me(3) Si) ((2) CNN.CNN的异构化和随后的三构化.
- 识别和描述反应中涉及的催化物种.
- 为了阐明反应机制,动力学和热力学.
主要方法:
- 涉及添加三甲基离子的实验研究.
- 介质异离子催化剂的表征.
- 密度函数理论 (DFT) 计算用于机械和热力学分析.
主要成果:
- 在添加[Me(3) Si](+) 离子时,观察到 (Me(3) Si) ((2) CNN 到 (Me(3) Si) ((2) NNC 的同质化.
- 一个独特的三元化反应只产生了4-diazenyl-3-hydrazinylpyrazole.
- 证实了异二离子的催化作用,[(Me(3) Si) ((2) NNC(SiMe(3)) ](+).
结论:
- 反应通过三步机制进行:二甲异构化,C-C或N-C合,以及正式的循环添加.
- DFT计算为反应的动力和热力学概况提供了洞察力.
- 这项工作揭示了一种新的合成途径,可以从化二甲中取代pyrazoles.
相关概念视频
Carboxylic Acids to Methylesters: Alkylation using Diazomethane
Carboxylic acids react with diazomethane in an ether solvent via alkylation at the carboxylate oxygen atom to give methyl esters of the corresponding acid with excellent yields.
[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.
Preparation and Reactions of Sulfides
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Arenediazonium substitution reactions occur when the diazonium group is substituted by various functional groups such as halides, hydroxyl, nitrile, etc. For instance, arenediazonium salts react with copper(I) salts of chloride, bromide, or cyanide to form corresponding aryl chlorides, bromides, and nitriles. These reactions are named Sandmeyer reactions. Although the mechanism of this reaction is complicated, as illustrated in Figure 1, they are believed to progress via an aryl copper...
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
The Diels–Alder reaction is one of the robust methods for synthesizing unsaturated six-membered rings. The reaction involves a concerted cyclic movement of six π electrons: four π electrons from the diene and two π electrons from the dienophile.


