ディメチルダイオキシラン C-H 酸化の分子動力学
Zhongyue Yang1, Peiyuan Yu1, K N Houk1
1Department of Chemistry and Biochemistry, University of California , Los Angeles, California 90095, United States.
Journal of the American Chemical Society
|March 12, 2016
まとめ
分子ダイナミクスのシミュレーションでは,アセトン溶媒におけるイソブタンによる酸素リバウンドに有利なダイメチルダイオキシラン (DMDO) の反応が示されている. トートブタノールとアセトンに至るこの経路は,障壁のない移行により溶液で非常に効率的になります.
科学分野:
- 物理化学
- コンピュータ化学
- 反応ダイナミクス
背景:
- ディメチルダイオキシラン (DMDO) は強力な酸化剤である.
- DMDO反応の仕組みを理解することは,合成化学にとって極めて重要です.
- 水素原子の抽出は,DMDO反応の重要なステップです.
研究 の 目的:
- 分子ダイナミクスを用いてイソブタンとDMDOの反応経路を調査する.
- DMDO反応の結果に対する溶媒の作用を解明する.
- 移行状態と中間種を特徴づける
主な方法:
- 分子ダイナミクスのシミュレーション
- 暗黙のアセトン溶媒モデル (SMD) を利用する.
- 反応経路を分析し,製品の分布と中間寿命を決定する.
主要な成果:
- ガス段階では,酸素リバウンド経路に従った反応軌道の10%しかなかった.
- 暗黙のアセトン溶剤では,酸素リバウンド経路は90%の効率に増加しました.
- 酸素リバウンド経路はアセトン溶液で無障碍になります.
- 短命のダイラジカル中間物質が観察され,C-H結合の断裂からC-O結合の形成は30~150fsで発生した.
結論:
- 溶媒の影響は,DMDOとイソブタンとの反応結果に大きく影響する.
- アセトン溶媒は 酸素リバウンド経路の効率を劇的に高めます
- 観察されたC−O結合形成の時間スケールは,類似の基質ペアの寿命に関する実験データと一致する.
さらに関連する動画
関連する概念動画
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
13.4K
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
13.4K
Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
8.0K
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
8.0K
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
13.7K
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.
13.7K
Preparation of Epoxides
9.8K
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...
9.8K
Radical Formation: Homolysis
4.6K
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 by one atom forming ions by the cleavage called heterolysis, or the two electrons are shared by two atoms, with one each creating radicals by the cleavage called homolysis.
4.6K
π Molecular Orbitals of 1,3-Butadiene
12.6K
Conjugated dienes have lower heats of hydrogenation than cumulated and isolated dienes, making them more stable. The enhanced stabilization of conjugated systems can be understood from their π molecular orbitals.
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
12.6K


