相关实验视频
Updated: Jul 3, 2026
09:58
Light-driven Enzymatic Decarboxylation
Published on: May 22, 2016
效率高的催化氧化基因的易斯酸/[Os(VI) ((N) Cl4]-使用过氧化物作为终端氧化剂. 证据表明一种基于金属的活性中间体
Shek-Man Yiu1, Wai-Lun Man, Tai-Chu Lau
1Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, China.
Journal of the American Chemical Society
|July 23, 2008
概括
这项研究引入了利用过氧化物对的有效的催化氧化,实现了高产量和营业额. 该机制避免了激素中间体,这表明基功能化的新型催化途径.
科学领域:
- 无机化学 无机化学
- 有机化学 有机化学
- 催化剂是一种催化剂.
背景情况:
- 烯氧化对于合成有价值的化学物质至关重要.
- 开发高效和选择性的氧化催化系统仍然是一个重大挑战.
- 过氧化物是常见的氧化剂,但它们在基功能化中的有效利用需要谨慎的催化剂设计.
研究的目的:
- 开发一种高效的催化系统,用于利用各种过氧化物进行氧化.
- 为了研究由奥斯复合物催化的氧化机制.
- 为了证明一种新型过氧化物MPPH作为终端氧化剂的实用性.
主要方法:
- 使用[Os(VI) ((N) Cl4](-) 作为易斯酸 (FeCl3或Sc(OTf) 的催化剂进行了基氧化反应3).
- 作为氧化剂,使用了各种过氧化物,包括三丁氧化 (tBuOOH),过氧化 (H2O2) 和2,2-二甲基氧化 (MPPH).
- 使用对激素中间体敏感的技术进行产品分析,例如涉及O2和BrCCl3的研究,以及立体化学分析.
主要成果:
- 催化系统有效地将环素氧化为环醇和环松,产量高,营业额超过7500 (用tBuOOH) 和1000 (用H2O2).
- 发现MPPH是一种有效的末端氧化剂,产生>70%的循环醇/循环松和>90%的MPPOH.
- 证据包括O2,BrCCl3的最小影响和完全的立体化学保留,表明一种非激进的机制涉及过氧化物的异质裂解.
结论:
- [Os(VI) ((N) Cl4](-) /路易斯酸系统为基氧化提供了一种高效和稳健的方法.
- 催化循环很可能通过O原子转移形成Os (VIII) 种,然后从中提取H原子,避免基中间体.
- 这项工作突出了在温和条件下选择性基功能化的有希望的催化方法.
相关概念视频
01:46Oxidative Cleavage of Alkenes: Ozonolysis
In ozonolysis, ozone is used to cleave a carbon–carbon double bond to form aldehydes and ketones, or carboxylic acids, depending on the work-up.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
Ozone is a symmetrical bent molecule stabilized by a resonance structure.
02:04Oxidation 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.
02:21Oxidation 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.
02:44Oxidation 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.
02:01Alkynes to Carboxylic Acids: Oxidative Cleavage
Alkynes undergo oxidative cleavage in the presence of oxidizing reagents like potassium permanganate and ozone. The triple bond — one σ bond and two π bonds — is completely cleaved, and the alkyne is oxidized to carboxylic acids. When warm and basic aqueous potassium permanganate is used as an oxidizing agent, alkynes are first converted to carboxylate salts via an unstable α-diketone intermediate. Further, a mild acid treatment protonates the carboxylate anions generating free carboxylic acid...
02:37Oxidation of Alcohols
In this lesson, the oxidation of alcohols is discussed in depth. The various reagents used for oxidation of primary and secondary alcohols are detailed, and their mechanism of action is provided.
The process of oxidation in a chemical reaction is observed in any of the three forms:
The process of oxidation in a chemical reaction is observed in any of the three forms: