アルカンの銅媒介脱水C ((sp3) -Hボリレーション
Ruocheng Sang1, Wangyujing Han1, Hanwen Zhang1
1School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K.
Journal of the American Chemical Society
|July 6, 2023
まとめ
銅塩化物 (CuCl2) は,アルケンのC-H結合の金属無,根幹媒介型ボリレーションを可能にします. この酸化物質のない方法は,原料の化学物質を有価なオルガノボロン反応剤に変換し,高原子経済を達成します.
科学分野:
- 有機化学
- カタリシス
- 持続可能な化学
背景:
- 惰性C−H結合のボリレーションは,原料化学物質からオルガノボロン反応剤を合成するために不可欠である.
- 伝統的に貴金属触媒は,脱水性ボリレーションを容易にする.
- 金属のない,光誘発の激素酸化は,代替の地域選択性を提供するが,ステキオキシダントを必要とし,原子経済を制限する.
研究 の 目的:
- 放射性物質によるC−Hボリル化のための酸化物質のない,金属のない触媒システムを開発する.
- 脱水性ボリレーションを促進する銅触媒の二重の役割を探求する.
- アルカンをオルガノボロン化合物に変換する際に高原子経済性を達成する.
主な方法:
- 塩化銅 (CuCl2) は,アルカンのC ((sp3) -H脱水媒介で触媒化される.
- ボリル化剤としてビスコラトディボロンを使用した.
- 銅触媒の二重作用を含む触媒サイクルを調査した.
主要な成果:
- CuCl2は,酸化物質のない,根幹媒介型脱水性C ((sp3) -Hボリレーションを効果的に触媒化する.
- 銅触媒は二重の役割を果たし,ディボロン反応剤を電性ビスボリオキシドに酸化する.
- この中間物質は,後の酸化還元中性光触媒C-Hボリレーションに参加し,効率を高めます.
結論:
- アルカンのC-Hボリレーションのための新しいCuCl2触媒化,酸化物質のない方法を開発した.
- 銅の独特の二重触媒機能が,根幹媒介型ボリレーションで示された.
- このアプローチは,既存のボリレーション方法に対して,持続可能で原子経済的な代替手段を提供している.
![[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
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
18.4K
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.
18.4K
03:08Hydroboration-Oxidation of Alkenes
8.4K
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
8.4K
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
7.8K
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.
7.8K
02:36Regioselectivity and Stereochemistry of Hydroboration
8.2K
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...
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...
8.2K
02:46Halogenation of Alkenes
15.8K
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.
15.8K
02:13Reduction of Alkenes: Catalytic Hydrogenation
12.2K
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...
12.2K