関連する実験動画
Updated: Jul 19, 2025
09:58
Light-driven Enzymatic Decarboxylation
Published on: May 22, 2016
11.7K
フォトレドックス触媒による水素原子移転とエナチオセレクティブ・プロトネーションによる非対称的なオレフィン異体化
Yang Liu1, Linghong Zhang1, Yong Zhang1
1Key Laboratory of Natural Medicine and Immuno-Engineering, Henan University, Kaifeng 475004, Henan, P. R. China.
Journal of the American Chemical Society
|August 8, 2023
まとめ
この研究は,非対称なオレフィン同体化のための新しいフォトレドックス触媒法を導入し,貴重なエナチオ濃縮分子の合成を可能にします. この戦略は熱力学的制約を克服し,有機合成の可能性を広げています.
科学分野:
- 有機化学
- カタリシス
- 非対称合成
背景:
- 非対称なオレフィンイソメリゼーションは,エナチオ濃縮分子にとって貴重な合成経路である.
- 限られた成功は,熱力学的好適性 (基板に対する製品の安定性) の要求による.
研究 の 目的:
- 熱力学的に不利な非対称なオレフィンイソメリゼーションに挑戦するための戦略を開発する.
- α-三次炭素ステレオセンターでエナチオ濃縮されたアリルアザレン誘導体を合成する.
主な方法:
- 可視光感受剤 (DPZ) とキラルリン酸を併用した二重触媒システムを使用した.
- N-ヒドロキシイミドによる光還元触媒性水素原子移転 (HAT) を採用した.
- デュテリウム源としてD2Oを使用した.
主要な成果:
- アリルアザレンの配列を 合成した
- 高い収穫量,エナティオメール過量 (ee),E/Z比率を達成した.
- ステレオセンターにデュテリウムが組み込まれていることが証明された.
結論:
- 開発された戦略は,熱力学的に不利な非対称なオレフィンイソメリゼーションを可能にします.
- この方法は,複雑な分子を合成するための幅広い適用性と有望な有用性を提供します.
- メカニズムの洞察は,反応性とエナチオ選択性の課題の理解を提供します.
関連する概念動画
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
3.4K
Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
3.4K
02:44Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
10.4K
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.
10.4K
02:13Reduction of Alkenes: Catalytic Hydrogenation
12.2K
Alkenes undergo reduction by the addition of molecular hydrogen to give alkanes. Because the process generally occurs in the presence of a transition-metal catalyst, the reaction is called catalytic hydrogenation.
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
Metals like palladium, platinum, and nickel are commonly used in their solid forms — fine powder on an inert surface. As these catalysts remain insoluble in the reaction mixture, they are referred to as heterogeneous catalysts.
The hydrogenation process takes place on the...
12.2K
01:25Radical Anti-Markovnikov Addition to Alkenes: Overview
3.4K
The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.
3.4K
02:36Regioselectivity and Stereochemistry of Hydroboration
8.2K
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
8.2K
03:08Hydroboration-Oxidation of Alkenes
8.4K
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
8.4K