库普里克超氧介导的分子间C-H激活化学
Ryan L Peterson1, Richard A Himes, Hiroaki Kotani
1Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States.
Journal of the American Chemical Society
|January 27, 2011
概括
一种新型的铜超氧复合物激活了NADH类似物中的C-H键. 这种通过动力学和同位素效应研究的仿生反应类似于铜单氧基酶活性.
科学领域:
- 生物有机化学 生物有机化学
- 有机金属化学 有机金属化学
背景情况:
- 复合铜在生物氧化反应中起着至关重要的作用.
- 了解仿生模型对于阐明酶机制至关重要.
研究的目的:
- 为了研究一种新的铜超氧复合物的C-H激活能力.
- 为了将这个复合物的反应性与已知的铜单氧酶进行比较.
主要方法:
- 铜超氧复合物的合成和表征 [LCu(II)(O2(•-))](+).
- 用1--1,4-二基胺胺 (BNAH) 进行分子间C-H激活反应的动力学研究.
- 测量了的动态同位素效应 (KIE).
主要成果:
- 铜超氧复合体证明了BNAH的分子间C-H激活.
- 动力分析显示了对铜复合体和BNAH.的第一级依赖.
- 观察到显著的KIE (12.1),表明与铜单氧化酶类似的机制.
结论:
- 研究的铜超氧复合物表现出生物模拟的C-H激活特性.
- 这些发现为铜催化氧化反应的机制提供了洞察力.
相关概念视频
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Some cycloaddition reactions are activated by heat, while others are initiated by light. For example, a [2 + 2] cycloaddition between two ethylene molecules occurs only in the presence of light. It is photochemically allowed but thermally forbidden.
Cycloaddition Reactions: MO Requirements for Thermal Activation
Thermal cycloadditions are reactions where the source of activation energy needed to initiate the reaction is provided in the form of heat. A typical example of a thermally-allowed cycloaddition is the Diels–Alder reaction, which is a [4 + 2] cycloaddition. In contrast, a [2 + 2] cycloaddition is thermally forbidden.
Photochemical Electrocyclic Reactions: Stereochemistry
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
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: 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: 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.

![[(DPEPhos)(bcp)Cu]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)
