![[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)
コバルト触媒は,アリルハリドによる環開きにおける地域選択性を決定する
Aleksandra Potrząsaj1, Mateusz Musiejuk1, Wojciech Chaładaj1
1Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
Journal of the American Chemical Society
|June 3, 2021
まとめ
この研究は,地域選択性エポキシードリング開封のための新しいビタミンB12/Ni二重触媒システムを導入します. この方法は,青い光を使用してアリルエポキシドとアリルハリドから線形製品を効率的に合成します.
科学分野:
- 有機合成
- カタリシス
- 写真化学
背景:
- エポキシードリング開きは基本的な有機変換であり,線形または分岐した製品を生成します.
- アリルエポキシドとアリルハリドの地域選択的クロスエレクトロフィール結合は,依然として重要な合成課題である.
研究 の 目的:
- アリルエポキシドとアリルハリドからの線形産物の地域選択合成のための新しい触媒システムを開発する.
- 主に枝分かれしたアルコールを生成する既存の方法を補完するためです.
主な方法:
- ビタミンB12とニッケル (Ni) を含む二重触媒系を用いた.
- 反応を誘導するために 青い光を照射した.
- 反応メカニズムを明らかにするために実験的および理論的研究を行った.
主要な成果:
- エポキシードリング開封による線形産物の選択合成を達成した.
- ビタミンB12/Niのダブル触媒システムの有効性を 青光照射で証明した.
- アルキルコバラミンは反応メカニズムにおける重要な中間物質として特定された.
結論:
- 開発されたビタミンB12/Niの二重触媒システムは,線形製品の地域選択合成のための新しい経路を提供します.
- この方法論は,特に分岐アルコールを入手するために,既存の経路に価値のある代替手段を提供します.
- この発見は,触媒性エポキシド変換とメカニズム的経路の理解を進めている.
関連する概念動画
02:24Acid-Catalyzed Ring-Opening of Epoxides
7.9K
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...
7.9K
02:26Base-Catalyzed Ring-Opening of Epoxides
9.1K
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...
9.1K
02:35Regioselectivity of Electrophilic Additions-Peroxide Effect
9.2K
In the presence of organic peroxides, the addition of hydrogen bromide to an alkene yields the isomer that is not predicted by Markovnikov’s rule. For example, the addition of hydrogen bromide to 2-methylpropene in the presence of peroxides gives 1-bromo-2-methylpropane. This addition reaction proceeds via a free radical mechanism, which reverses the regioselectivity. The free radical reaction mechanism involves three stages: initiation, propagation, and termination.
9.2K
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
15.1K
If a set of reactants can yield multiple constitutional isomers, but one of the isomers is obtained as the major product, the reaction is said to be regioselective. In such reactions, bond formation or breaking is favored at one reaction site over others.
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
The hydrohalogenation of an unsymmetrical alkene can yield two haloalkane products, depending on which vinylic carbon takes up the halogen. However, one product usually predominates, where hydrogen adds to the vinylic carbon bearing the...
15.1K
02:57Sharpless Epoxidation
4.5K
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...
4.5K
03:00Preparation of Epoxides
8.4K
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...
8.4K