1-(2-エチニルフェニル) -3,3-ダイアルキルトリアゼンのサイクル化におけるメカニズム的二分法を解読:ペリサイクリック経路と偽コアクトート経路の競争
David B Kimball1, Timothy J R Weakley, Rainer Herges
1Department of Chemistry, University of Oregon, Eugene 97403-1253, USA.
Journal of the American Chemical Society
|November 7, 2002
まとめ
本研究では, (2-エチニルフェニル) トリアゼネスのサイクリングメカニズムを調査しています. カーベンとペリサイクル経路を含む異なる経路は,イソインダゾールやシナリンなどの様々な製品につながります.
科学分野:
- 有機化学 オーガニック・ケミストリー
- 反応メカニズム 反応メカニズム
背景:
- 循環反応は,有機合成において根本的な役割を果たします.
- 反応経路を理解することは,製品形成の制御に極めて重要です.
研究 の 目的:
- (2-エチニルフェニル) トリアゼンサイクル化のメカニズム的経路を解明する.
- 熱的および銅媒介反応条件の両方を調査するために.
- 主要な中間物質と反応産物を特定する.
主な方法:
- (2-エチニルフェニル) トリアゼンを熱および銅媒介条件下での実験研究.
- 密度関数理論 (DFT) 計算.密度関数理論 (DFT) 計算.密度関数理論 (DFT) 計算.密度関数理論 (DFT) 計算.密度関数理論 (DFT) 計算.密度関数理論 (DFT) 計算.密度関数理論 (DFT) 計算.
- デウテリウム捕獲に関する研究.
主要な成果:
- イソインダゾール形成にはカルベンの経路が提案されており,中介物質は酸素,二酸化,またはトラッピングに敏感です.
- DFTの計算は,カルベンの形成のための偽コアクトート経路を支持しています.
- シノリンの形成には,実験的なトラッピングによってサポートされる,ズウィトリアン系デヒドロシノリニウム中間体を通じたペリサイクリック経路が提案されています.
結論:
- (2-エチニルフェニル) トライアゼンの循環は,条件によって異なるメカニズム的な経路を経由します.
- カーベンとペリサイクルの経路は,異なるヘテロサイクルの生成を決定する.
- 計算および実験データは,提案されたメカニズムに強力な支持を提供します.
関連する概念動画
01:57Preparation of Diols and Pinacol Rearrangement
Compounds bearing two hydroxyl groups are known as diols. When the hydroxyl groups are located on adjacent carbon atoms, the diols are called vicinal diols or glycols. Under acidic conditions, vicinal diols undergo a specific reaction called pinacol rearrangement.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
03:00Preparation of Epoxides
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
01:17Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
![[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2Ffiles%2Fmedia%2Fscience-education%2Fscience-education-thumbs%2F12422.jpg&w=3840&q=75)
01:21[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
The Cope rearrangement is classified as a [3,3] sigmatropic shift in 1,5-dienes, leading to a more stable, isomeric 1,5-diene. The reaction involves a concerted movement of six electrons, four from two π bonds and two from a σ bond, via an energetically favorable chair-like transition state.
01:17Pericyclic Reactions: Introduction
Pericyclic reactions are organic reactions that occur via a concerted mechanism without generating any intermediates. The reactions proceed through the movement of electrons in a closed loop to form a cyclic transition state, where rearrangement of the σ and π bonds yields specific products.
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic rearrangements are...
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic rearrangements are...