直接迈克尔添加的基因通过-dinitrosyl介导的C-H功能化反应反应
Chen Zhao1, F Dean Toste, Robert G Bergman
1Department of Chemistry, University of California, Berkeley, California 94720, USA.
Journal of the American Chemical Society
|June 25, 2011
概括
这项研究引入了使用-基复合体的基的直接C-H功能化. 单方法有效合成循环,不和化合物,显示催化潜力.
科学领域:
- 有机金属化学 有机金属化学
- 有机合成 有机合成
- 催化剂是一种催化剂.
背景情况:
- 直接的C-H功能化为复杂分子提供了更为原子经济的途径.
- 在有机转化中,-基复合物提供了独特的反应性.
- 循环,不和化合物的高效合成仍然是有机化学的一个关键挑战.
研究的目的:
- 开发一种单,直接的基因的C-H功能化反应.
- 为了利用-酸盐复合物作为这种转换的媒介.
- 合成循环四基替代,γ,δ不和化合物.
主要方法:
- 采用了一个单反应程序.
- 基的直接C-H功能化是由[CpCo ((NO) ((2)) ] (环乙烯基丁) 介导的.
- 进行了所有反应中间体的表征.
主要成果:
- 反应成功产生了循环四基替代,γ,δ不和化合物.
- 多种迈克尔接受器与该程序兼容.
- 取得了良好的产品收益率.
结论:
- 开发的单方法提供了一条有效的途径,以获得有价值的循环不和化合物.
- 该反应证明了[CpCo(NO)(2) ]在直接的C-H功能化中的实用性.
- 初步结果表明催化转换的潜力,建议未来在可持续合成中的应用.
相关概念视频
Conjugate Addition of Enolates: Michael Addition
The attack of a nucleophile at the β carbon of an α,β-unsaturated carbonyl compound is called conjugate addition. Conjugate addition reactions of active methylene compounds, such as β-diketones, β-keto esters, β-keto nitriles, and α-nitro ketones, are called Michael addition reactions.
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Robinson annulation is a base-catalyzed reaction for the synthesis of 2-cyclohexenone derivatives from 1,3-dicarbonyl donors (such as cyclic diketones, β-ketoesters, or β-diketones) and α,β-unsaturated carbonyl acceptors. Named after Sir Robert Robinson, who discovered it, this reaction yields a six-membered ring with three new C–C bonds (two σ bonds and one π bond).
Electrophilic Addition to Alkynes: Hydrohalogenation
Electrophilic addition of hydrogen halides, HX (X = Cl, Br or I) to alkenes forms alkyl halides as per Markovnikov's rule, where the hydrogen gets added to the less substituted carbon of the double bond. Hydrohalogenation of alkynes takes place in a similar manner, with the first addition of HX forming a vinyl halide and the second giving a geminal dihalide.
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.
Radical Anti-Markovnikov Addition to Alkenes: Mechanism
The reaction of hydrogen bromide with alkenes in the presence of hydroperoxides or peroxides proceeds via anti-Markovnikov addition. The radical chain reaction comprises initiation, propagation, and termination steps.
The mechanism starts with chain initiation, which involves two steps. In the first chain initiation step, a weak peroxide bond is homolytically cleaved upon mild heating to form two alkoxy radicals. In the second initiation step, a hydrogen atom is abstracted by the alkoxy radical...
The mechanism starts with chain initiation, which involves two steps. In the first chain initiation step, a weak peroxide bond is homolytically cleaved upon mild heating to form two alkoxy radicals. In the second initiation step, a hydrogen atom is abstracted by the alkoxy radical...
Alkenes via Reductive Coupling of Aldehydes or Ketones: McMurry Reaction
The radical dimerization of ketones or aldehydes gives vicinal diols through a pinacol coupling reaction. However, the behavior of titanium metals used for the reaction as a source of electrons is unusual. When the reaction is carried out in the presence of titanium, diols can be isolated at low temperatures. Else titanium further reacts with diols, forming alkenes through the McMurry reaction.


