銅ナノ結晶平面は,アロマティックエポキシドの触媒脱酸素化のステレオ選択性に対する効果である
Bin Xiao1,2,3, Zhiqiang Niu2,3, Yang-Gang Wang2,3
1†Center of Advanced Nanocatalysis (CAN), University of Science and Technology of China, Hefei 230026, China.
Journal of the American Chemical Society
|March 18, 2015
まとめ
触媒の結晶平面は,反応のステレオ選択性に著しく影響する. 銅ナノ結晶は,脱酸素反応におけるシス/トランスオレフィン生成の制御を可能にし,新しい合成経路を提供する.
科学分野:
- 異質なカタリシスである.
- 有機合成による有機合成です.
- マテリアルサイエンス 材料科学
背景:
- 異質な触媒の結晶平面は,活性と選択性を高めることができます.
- 触媒反応におけるステレオ選択性の制御は,特定の同位体合成に不可欠である.
研究 の 目的:
- アロマティックエポキシドの銅触媒による脱酸素化のステレオ選択性に対する触媒結晶平面の効果を調査する.
- 観察されたステレオ選択性の変化の背後にあるメカニズムを理解する.
主な方法:
- 定義された結晶平面 (立方体,ワイヤ,プレート) の銅ナノ結晶の合成と特徴付け.
- アロマティックエポキシドの銅触媒による脱酸素反応.
- シス/トランスオレフィン製品の比率の分析.
- スキャントンネル顕微鏡 (STM) と密度関数理論 (DFT) の研究.
主要な成果:
- 異なる銅結晶平面 (立方体,ワイヤ,プレート) は,エポキシド脱酸素化において異なったシス/トランス選択性を示した.
- 均質な銅触媒は,劣ったステレオ選択性を示した.
- STMとDFTは,Cu{100}平面におけるエポキシド酸素の吸附モードと強度が選択性に影響することを明らかにした.
結論:
- 触媒結晶平面工学は,有機反応におけるステレオ選択性を制御するための戦略を提供します.
- 銅触媒による脱酸素化は,芳香系エポキシドからシスオレフィンを合成するための実用的な方法を提供します.
- ナノクリスタル触媒は,触媒の立体化学制御に使用することができます.
![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
関連する概念動画
02:24Acid-Catalyzed Ring-Opening of Epoxides
9.9K
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
9.9K
02:57Sharpless Epoxidation
5.5K
The conversion of allylic alcohols into epoxides using the chiral catalyst was discovered by K. Barry Sharpless and is known as Sharpless epoxidation. The use of a chiral catalyst enables the formation of one enantiomer of the product in excess. This chiral catalyst is mainly a chiral complex of titanium tetraisopropoxide and tartrate ester (specific stereoisomer). The stereoisomer used in the chiral catalyst dictates the formation of the enantiomer of the product. In other words, the use of...
5.5K
02:26Base-Catalyzed Ring-Opening of Epoxides
11.2K
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
11.2K
03:00Preparation of Epoxides
10.0K
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...
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...
10.0K
02:04Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids
8.3K
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.
8.3K
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
13.7K
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.
13.7K