関連する実験動画
Updated: Jul 8, 2026
11:00
Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
パラジウムアセテートによって触媒化されたsp3C-H結合の高度に地域選択的アリレーション
Vladimir G Zaitsev1, Dmitry Shabashov, Olafs Daugulis
1Department of Chemistry, University of Houston, Houston, Texas 77204-5003, USA.
Journal of the American Chemical Society
|September 22, 2005
まとめ
パラジウムで触媒化された新しいC-H活性化法により,カルボキシル酸とアミンの選択的アリレーションが可能になる. この多用途なプロセスは,指向グループを使用して,様々なsp3およびsp2C-H結合を効率的に機能化します.
科学分野:
- 有機化学 オーガニック・ケミストリー
- カタリシス カタリシス カタリシス
- 合成方法論 合成方法論
背景:
- C-Hアクティベーションは,従来慣性のない結合を機能化するための直接的な経路を提供します.
- パラジウム触媒は,現代の有機合成の強力なツールです.
- C-H機能化のための選択的方法の開発は,依然として重要な課題です.
研究 の 目的:
- パラジウム触媒による新しいアリレーション反応を開発するために.
- カーボキシル酸誘導体の選択的β-アリレーションとアミン誘導体のガンマ-アリレーションを可能にします.
- この過程におけるC−H結合の活性化の範囲を調査する.
主な方法:
- ピリジンを含有する誘導基を用いる.
- C-Hの活性化とアリレーションのために,パラジウム触媒を用いる.
- 主要および二次 sp3 C-H 結合,および sp2 C-H 結合の反応性を調査する.
主要な成果:
- C-H活性化に基づく新しいパラジウム触媒のアリレーションプロセスが成功裏に開発されました.
- この方法は,カルボキシル酸誘導体の地域選択的β-アリレーションを可能にします.
- この方法は,アミン誘導体の地域選択的ガンマアリレーションも可能にします.
- sp3 C-H 債券と sp2 C-H 債券の両方が反応性があることが示されました.
結論:
- 開発された方法は,C-Hアリレーションに多岐にわたるアプローチを提供します.
- 指導グループの使用は,地域選択性を達成するために不可欠です.
- この方法論は,複雑な有機分子を合成するためのツールキットを拡張します.
関連する概念動画
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
02:34Molecular Structure and Acidity
An acid can be deprotonated to form a conjugate base or an anion. If the produced anion is more stable, then the acid is stronger. On the contrary, if the anion is unstable, then the acid is weaker. Hence, to determine the acidity of the compound, the stability of its conjugate base is studied using various factors.
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
The size effect explains the change in atomic size on acidity. When comparing the acids formed from elements that belong to the same column in the periodic table, their atomic sizes...
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...
02:35Regioselectivity of Electrophilic Additions-Peroxide Effect
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.
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.
02:36Regioselectivity and Stereochemistry of Hydroboration
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 stereochemistry.
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 stereochemistry.