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相关概念视频

Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide02:44

Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide

Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
Oxidation of Alkenes: Syn Dihydroxylation with Potassium Permanganate02:21

Oxidation of Alkenes: Syn Dihydroxylation with Potassium Permanganate

Alkenes can be dihydroxylated using potassium permanganate. The method encompasses the reaction of an alkene with a cold, dilute solution of potassium permanganate under basic conditions to form a cis-diol along with a brown precipitate of manganese dioxide.
Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids02:04

Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids

Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation02:17

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

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...
Acid-Catalyzed α-Halogenation of Aldehydes and Ketones01:21

Acid-Catalyzed α-Halogenation of Aldehydes and Ketones

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...
Radical Oxidation of Allylic and Benzylic Alcohols01:21

Radical Oxidation of Allylic and Benzylic Alcohols

Activated manganese(IV) oxide can selectively oxidize allylic and benzylic alcohols via a radical intermediate mechanism. Primary allylic alcohols are oxidized to aldehydes, while secondary allylic alcohols yield ketones. The redox reaction of potassium permanganate with an Mn(II) salt such as manganese sulfate (under either alkaline or acidic conditions), followed by thorough drying, yields the oxidizing agent: activated MnO2. While MnO2 is insoluble in the solvents used for the reaction, the...

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相关实验视频

Updated: Jul 12, 2026

Temperature-programmed Deoxygenation of Acetic Acid on Molybdenum Carbide Catalysts
08:15

Temperature-programmed Deoxygenation of Acetic Acid on Molybdenum Carbide Catalysts

Published on: February 7, 2017

cis-Dihydroxylation和阿尔基因的环氧化通过[Mn(2) O(RCO(2)) (((2) ((tmtacn) ((2)):调整一个高效的H(2) O(2) 催化剂的选择性.

Johannes W de Boer1, Jelle Brinksma, Wesley R Browne

  • 1Department of Organic and Molecular Inorganic Chemistry, Stratingh Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.

Journal of the American Chemical Society
|June 2, 2005
PubMed
概括
此摘要是机器生成的。

碳氧酸增强催化剂,用于使用过氧化的基 cis-dihydroxylation 和环氧化. 该系统提供可调节的选择性和高活性,这代表了在无OS催化中取得的重大进展.

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Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
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Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Published on: June 21, 2017

Tuning the Acidity of Pt/ CNTs Catalysts for Hydrodeoxygenation of Diphenyl Ether
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Tuning the Acidity of Pt/ CNTs Catalysts for Hydrodeoxygenation of Diphenyl Ether

Published on: August 17, 2019

相关实验视频

Last Updated: Jul 12, 2026

Temperature-programmed Deoxygenation of Acetic Acid on Molybdenum Carbide Catalysts
08:15

Temperature-programmed Deoxygenation of Acetic Acid on Molybdenum Carbide Catalysts

Published on: February 7, 2017

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
06:46

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Published on: June 21, 2017

Tuning the Acidity of Pt/ CNTs Catalysts for Hydrodeoxygenation of Diphenyl Ether
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Tuning the Acidity of Pt/ CNTs Catalysts for Hydrodeoxygenation of Diphenyl Ether

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科学领域:

  • 有机金属化学 有机金属化学
  • 催化剂是一种催化剂.
  • 绿色化学 绿色化学

背景情况:

  • 复合物被探索为氧化反应的催化剂.
  • 过氧化是一种绿色氧化剂,但其使用可能受到催化剂稳定性和选择性的限制.
  • 开发高效和选择性的氧化催化剂对于可持续的化学合成至关重要.

研究的目的:

  • 为了描述碳酸酸促进的基的 cis-dihydroxylation 和环氧化.
  • 研究碳酸在调整双核催化剂的选择性和活性中的作用.
  • 为了证明碳酸盐配体在控制双核催化剂性能方面的潜力.

主要方法:

  • 使用[MnIV2O3(tmtacn) ]2+ (1) 的催化剂,其中H2O2作为氧化剂.
  • 在现场形成碳酸盐桥架双核复合物.
  • 谱学研究和X射线分析以表征中间体.
  • 评估催化剂活性和选择性与不同的碳酸盐.

主要成果:

  • 碳酸有效抑制了催化酶的活性,调整了催化剂的选择性.
  • 在现场证实了碳酸盐桥接双核复合体 (例如2,3) 的形成.
  • 双核Mn基催化剂的可调节选择性和活性首次被证明.
  • 该系统在cis-cyclooctanediol形成方面实现了高周转率 (高达2000).

结论:

  • 碳氧酸是催化氧化的有效催化剂.
  • 该系统代表了迄今为止报告的最活跃的无氧化物cis-dihydroxylation催化剂.
  • 这项工作为设计可调节的双核催化剂用于选择性氧化反应开辟了新的途径.