リガンドおよびカチオンパラメータの体系的な変動は,基板-リガンドの静電相互作用を通じて多重塩化アレーンのサイト選択C-CおよびC-Nクロスカップリングを可能にします
William A Golding1, Hendrik L Schmitt1, Robert J Phipps1
1Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom.
Journal of the American Chemical Society
|December 17, 2020
まとめ
研究者は,塩素化アレンの正確な部位選択的クロスカップリングのための多機能リガンド/塩基ツールキットを開発した. この方法は,複雑な分子に対する反応の制御における課題を克服し,高度に置換されたアレンの合成を可能にします.
科学分野:
- 有機化学
- キャタリシス
- 合成方法論
背景:
- 化学反応における位置選択性を制御することは 複雑な分子を合成するのに不可欠です
- 非共振相互作用は,反応性を誘導するための有望な戦略を提供しますが,密接な距離の場所での静電相互作用の有効性は議論されています.
- 多重塩素化アレンの部位選択的クロスカップリングは,しばしば従来の方法で複雑な混合物につながります.
研究 の 目的:
- 静電相互作用を用いて,部位選択のクロスカップリング反応を精密制御する可能性を調査する.
- 多重塩素化アレンのスズキ・ミヤウラとブッチャウォルド・ハートウィッグ結合における位置選択性を制御するための実用的なツールキットを開発する.
- サイト・セレクティブ・クロスカップリングによる複雑で高度に置換されたアレンの合成を実証する.
主な方法:
- 硫化フォスフィンリガンド2つと異なるサイズの塩基5つを含む10ピースのツールキットの適用.
- Suzuki-MiyauraとBuchwald-Hartwigの結合反応のためのリガンド/塩基組み合わせの体系的なスクリーニング.
- この方法の試験は,異合体二塩化および三塩化アレン基板の範囲で行われます.
主要な成果:
- リガンド/塩基の組み合わせは,クロスカップリング反応におけるサイト選択性を効果的に制御した.
- Suzuki-MiyauraとBuchwald-Hartwigの成功カップリングは,挑戦的な同位体塩素化アレンで達成されました.
- 開発された方法は,標準リガンドで典型的に観察される不治の混合物の形成を回避した.
結論:
- 慎重に選択されたリガンド/塩基組合せによる微調整された静電相互作用は,位置選択性を正確に制御することを可能にします.
- このツールキットは,サイト選択クロスカップリングのための実用的な解決策を提供し,複雑なポリ置換アレンの合成を容易にします.
- このアプローチは,複雑なアロマティック構造を構築するためのクロスカップリング反応の合成的有用性を拡張します.
さらに関連する動画
12:08Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes
Published on: June 24, 2022
3.8K
07:20Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents
Published on: May 28, 2014
14.2K
関連する概念動画
02:17Regioselectivity of Electrophilic Additions to Alkenes: Markovnikov's Rule
15.7K
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...
15.7K
01:15Electrophilic Aromatic Substitution: Chlorination and Bromination of Benzene
9.9K
Chlorination and bromination are important classes of electrophilic aromatic substitutions, where benzene reacts with chlorine or bromine in the presence of a Lewis acid catalyst to give halogenated substitution products. A Lewis acid such as aluminium chloride or ferric chloride catalyzes the chlorination, and ferric bromide catalyzes the bromination reactions. During the bromination of alkenes, bromine polarizes and becomes electrophilic. However, in the bromination of benzene, the bromine...
9.9K
01:17Thermal Electrocyclic Reactions: Stereochemistry
2.3K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.3K
01:27¹H NMR: Long-Range Coupling
2.3K
The coupling interactions of nuclei across four or more bonds are usually weak, with J values less than 1 Hz. While these are usually not observed in spectra, the presence of multiple bonds along the coupling pathway can result in observable long-range coupling.
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
In alkenes, spin information is communicated via σ–π overlap, as seen in allylic (four-bond) and homoallylic (five-bond) couplings. These coupling interactions are stronger when the σ bond is parallel to the alkene...
2.3K
01:19Complexation Equilibria: The Chelate Effect
894
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...
894
02:34Structural Isomerism
20.8K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
20.8K