誘導ハロゲン原子移転 (DIXAT):アリルラジカルを遠隔C ((sp3) -H機能化に向けて化学選択的に生成するための強力なツール
Sidhant Wagulde1, Kevin P Quirion2, Turki M Alturaifi2
1Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080-3021, United States.
Journal of the American Chemical Society
|August 1, 2025
まとめ
新しい誘導ハロゲン原子移転法 (DIXAT) は,伝統的な反応性傾向を克服し,アリルイオジドに対するアリルブロミドの選択的活性化を可能にします. この突破は,高度な化学合成のためのアリルラジカルを生成する際の正確な制御を可能にします.
科学分野:
- 有機化学
- キャタリシス
- ラジカル・ケミストリー
背景:
- ハロゲン原子移転 (XAT) と単一の電子移転 (SET) は,アリル基生成の一般的な方法である.
- XATとSETの反応性は,通常,結合解離エネルギーと還元ポテンシャルによって支配され,アリルブロミドよりもアリルヨウ素を好む.
- 既存の方法は,これらの固有の反応性傾向を克服できません.
研究 の 目的:
- アリル基生成における典型的な反応性傾向を逆転させる新しい戦略を開発する.
- アリルイオジドの存在下でも,アリルブロミドの化学選択的活性化を可能にします.
- 空間的指向に基づいたアリル根の生成を正確に制御する.
主な方法:
- 誘導ハロゲン原子移転 (DIXAT) 戦略の開発
- ニッケル触媒によるアリレーション反応のためにDIXATを使用する.
- アリファティックアミンの遠隔C ((sp3) -H結合のカスケードカルボアリレーションにおけるDIXATの適用.
- 1,6-または1,7-HATプロセスを介してサイト選択的なC-H機能化のためのテッダード補助装置を使用します.
主要な成果:
- DIXATは,BDEや還元ポテンシャルに関係なく,アリルイオジドよりもアリルブロミドを選択的に活性化します.
- この方法は,指向された活性化によるアリル基生成の正確な制御を可能にします.
- 遅段階の改変を含むアリファティックアミンのニッケル触媒化C-H機能化における成功応用.
- 操作の簡素性,高機能グループ耐性,広範囲の基板範囲が実証されています.
結論:
- DIXAT戦略は,アリル基の生成を制御する上で重要な進歩を表しています.
- この方法は,従来のXATおよびSETプロセスの固有の反応性の制限を克服します.
- 開発された技術は,特に複雑な分子において,選択的なC-H機能化のための強力なツールを提供します.
さらに関連する動画
07:50Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
9.4K
06:49Atom Transfer Radical Polymerization of Functionalized Vinyl Monomers Using Perylene as a Visible Light Photocatalyst
Published on: April 22, 2016
11.9K
関連する概念動画
01:19Diazonium Group Substitution: –OH and –H
2.9K
Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.
2.9K
02:46Halogenation of Alkenes
16.5K
Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
16.5K
02:38Electrophilic Addition to Alkynes: Halogenation
8.7K
Introduction
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
8.7K
01:27Radical Substitution: Halogenation of Alkanes and Alkyl Substituents
8.5K
In the presence of heat or light, alkanes react with molecular halogens to form alkyl halides by a substitution reaction called radical halogenation. This reaction has three steps: initiation, propagation, and termination, as seen in the radical chlorination of methane to produce methyl chloride.
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
8.5K
01:26Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
1.9K
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation...
1.9K
01:31Radical Substitution: Allylic Chlorination
2.5K
Typically, when alkenes react with halogens at low temperatures, an addition reaction occurs. However, upon increasing the temperature or under reaction conditions that form radicals, providing a low but steady concentration of halogen radicals, allylic substitution reaction is favored. This is because allylic hydrogens are very reactive as the formed intermediate is resonance stabilized. For example, when propene is treated with chlorine in the gas phase at 400 °C, it undergoes allylic...
2.5K