使用过氧化对未被激活的3度C-H键进行氧化介导的催化氧化
Benjamin H Brodsky1, J Du Bois
1Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
Journal of the American Chemical Society
|November 3, 2005
概括
研究人员开发了基于佐沙的新型氧化素,用于选择性C-H氧化和烯环氧化. 这些催化剂,使用disenide共催化剂和尿素过氧化,对三级C-H键具有很高的选择性,并氧化缺电子的烯酸.
科学领域:
- 有机化学 有机化学
- 催化剂是一种催化剂.
- 氧化反应 氧化反应
背景情况:
- 选择性氧化C-H键仍然是合成化学的一个重大挑战.
- 为合成复杂分子开发有效的C-H氧化和烯环氧化催化剂至关重要.
研究的目的:
- 设计,描述和评估基于1,2,3-焦酸的新型氧化素作为O原子转移剂.
- 探索它们在催化C-H氧化和烯环氧化中的有效性.
- 为了研究这些反应的选择性.
主要方法:
- 合成和结构性表征基于佐撒的氧齐里丁.
- 催化测试C-H氧化,使用diaryl diselenide共催化剂和尿素过氧化.
- 对烯环氧化进行催化试验.
主要成果:
- 开发的氧化素作为强大的O原子转移剂起作用.
- 催化C-H氧化证明了对三级C-H键的强烈选择性.
- 实现了终端和缺电子烯的有效环氧化.
结论:
- 基于本佐撒提亚的氧化是一种有前途的新类催化剂,用于选择性氧化.
- 这些发现推动了对选择性C-H氧化一般方法的开发.
- 催化剂系统显示了在有机合成中广泛应用的潜力.
相关概念视频
Catalysis
The presence of a catalyst affects the rate of a chemical reaction. A catalyst is a substance that can increase the reaction rate without being consumed during the process. A basic comprehension of a catalysts’ role during chemical reactions can be understood from the concept of reaction mechanisms and energy diagrams.
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 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 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.
Oxidative 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.
Catalysis
Catalysis influences the rate of chemical reactions by providing an alternative reaction pathway with lower activation energy. A catalyst speeds up a reaction, but it is not consumed during the process. The fundamental principle of catalysis is the ability of a catalyst to alter the reaction mechanism, often introducing a more efficient pathway than the uncatalyzed process.In a catalyzed reaction, the catalyst participates directly in the reaction mechanism. It interacts with reactants to form...


