銅触媒化アニリドC−H結合アリレーションにおける予期せぬメタ選択性のメカニズム的理解
Bo Chen1, Xue-Long Hou, Yu-Xue Li
1Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry , Chinese Academy of Sciences, 345 Ling Ling Road, Shanghai 200032, China.
Journal of the American Chemical Society
|April 28, 2011
まとめ
銅で触媒化されたアリレーションは,ヘックのような経路を通って予期せぬメタ製品を形成する. メトキシ群は,Cu (I) 触媒の運動研究によって支持された電友置換によるオルト製品形成を誘導する.
科学分野:
- 有機金属化学 有機金属化学
- 反応メカニズム 反応メカニズム
- コンピューティング・ケミストリー
背景:
- 銅で触媒化されたC-N結合形成は,有機合成において極めて重要です.
- アリレーション反応における地域選択性を理解することは,依然として課題です.
研究 の 目的:
- アニリデスの銅触媒アリレーションのメカニズムを解明する.
- 予期せぬメタ製品の形成を説明するために.
- 地域選択性における置換効果の役割を調査する.
主な方法:
- 密度関数理論 (DFT) による計算.
- 運動学的研究.
- 実験反応のモニタリング.
主要な成果:
- DFTは,メタ製品形成のためのCu (III) -Ph種を含むHeckのような四つ組のリングの移行状態を示唆しています.
- 競争力のある電友置換機構は,メタメトキシ基が存在すると,オルト製品を生成します.
- 運動データを含む実験的証拠は,Cu (I) 触媒の関与を支持しています.
結論:
- この研究は,銅で触媒化されたアニリドアリレーションにおける二重メカニズムを明らかにしている.
- 地域選択性は,置換物の電子効果と移行状態の幾何学によって制御されます.
- A Cu (I) / Cu (III) 触媒サイクルが提案されている.
関連する概念動画
02:17Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
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...
01:11ortho–para-Directing Activators: –CH3, –OH, –NH2, –OCH3
All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
01:11Nucleophilic Aromatic Substitution: Elimination–Addition
Simple aryl halides do not react with nucleophiles. However, nucleophilic aromatic substitutions can be forced under certain conditions, such as high temperatures or strong bases. The mechanism of substitution under such conditions involves the highly unstable and reactive benzyne intermediate. Benzyne contains equivalent carbon centers at both ends of the triple bond, each of which is equally susceptible to nucleophilic attack. This 50–50 distribution of products is confirmed through isotopic...
01:25Radical Anti-Markovnikov Addition to Alkenes: Overview
The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
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...
02:34Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.