氨酸氧化催化由-复合体催化
Michael C Haibach1, Changjian Guan, David Y Wang
1Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey , New Brunswick, New Jersey 08903, United States.
Journal of the American Chemical Society
|September 14, 2013
概括
的钉复合物催化了一个新的,原子经济的合成从olefins的aryl基乙烯. 这种有机金属方法避免了酸性催化剂,为工业应用提供了高选择性.
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.
- 有机合成 有机合成
背景情况:
- 基乙烯是重要的工业化学品,通常通过威廉姆森乙烯合成合成.
- 氨酸氧化呈现出一种更为原子经济的替代方案,但由于酸性催化剂的选择性较差而受到影响.
- 现有的过渡金属催化剂通常依赖于不良的布伦斯特德酸通路.
研究的目的:
- 开发一种高度选择性和原子经济的方法来合成基乙烯.
- 探讨使用的具复合物作为分子间氧化催化剂.
- 阐明催化机制,将其与已知的酸性通路区分开来.
主要方法:
- 采用的器复合物用于有机金属催化分子间的未激活的烯酸的氧化.
- 研究的反应途径,区别于布伦斯特酸催化剂.
- 反应中间体和产品的特征.
主要成果:
- 实现了高化学和区域选择性合成的基乙烯.
- 证明催化剂不会通过隐藏的布伦斯特德酸通路运行.
- 提出了一种涉及将烯插入氧化物键的机制,其次是C-H的减少性消除.
结论:
- 有机金属催化剂与针复合体提供了一条通往原子经济合成的新途径.
- 这种方法提供了一个选择性的替代传统的威廉姆森乙合成.
- 这些发现为合成各种氧化物开辟了道路.
相关概念视频
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.
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
02:17Reduction 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...
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...
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.
01:22Alkenes 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.
02:34Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.