アリファティックC-H結合の光化学的に媒介されたニッケル触媒 (ヘテロ) アリレーション
R Thomas Simons1, Meganathan Nandakumar1, Kitae Kwon1
1Department of Chemistry, Duke University, Box 90346, Durham, North Carolina 27708, United States.
Journal of the American Chemical Society
|February 13, 2023
まとめ
この研究は,非活性化アルキルC-H結合の直接アリレーションを可能にするサイト選択C-H機能化のための新しい方法を導入し,効率的なクロスカップリング反応のためにニッケル触媒とフォトレドックス化学を使用します.
科学分野:
- 有機化学
- カタリシス
- 合成方法論
背景:
- 活性化されていないC ((sp3) -H結合は,その強さと普遍性のために機能化することが困難である.
- 以前のC−Hアリレーションの方法は,しばしば窒素センターの前酸化を必要とする.
研究 の 目的:
- 直接のC−H機能化のための位置選択C−sp3−C−sp2クロスカップリング反応を開発する.
- 軽い条件下で活性化されていないアルキルC-H結合のアリレーションを可能にします.
主な方法:
- フォトレドックス可能な分子とニッケル前触媒を触媒クロスカップリングに使用した.
- 1,6-水素原子移転 (HAT) プロセスは,ペンダントアルコールを固定した硫酸エステルによって導かれます.
- 窒素酸化を先行せずに,N-H結合から直接変換を行う.
主要な成果:
- アリルブロミドとの非活性化アルキルC-H結合のサイト選択C-H機能化を達成した.
- 優れた選択性を持つ二次C-Hセンターでの効率的なアリレーションが実証されています.
- 開発されたクロスカップリング反応で良好な収量が報告されています.
結論:
- 開発された方法は,直接のC−Hアリレーションのための新しいアプローチを提供します.
- この戦略は,以前のC-H機能化技術の限界を克服します.
- この反応は複雑な有機分子を 合成する貴重なツールとなります
![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
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
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
7.9K
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
7.9K
02:13Reduction of Alkenes: Catalytic Hydrogenation
12.3K
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...
12.3K
01:21Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
4.0K
By replacing an α-hydrogen with a halogen, acid-catalyzed α-halogenation of aldehydes or ketones yields a monohalogenated product
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
4.0K
02:27Preparation of Alkynes: Alkylation Reaction
10.4K
Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.
10.4K
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
18.6K
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
18.6K