威尔金森催化剂的类型和意想不到的Ph-Cl激活
Vladimir V Grushin1, William J Marshall
1Central Research & Development, E. I. DuPont de Nemours and Co., Inc., Experimental Station, Wilmington, Delaware 19880-0328, USA. vlad.grushin-1@usa.dupont.com
Journal of the American Chemical Society
|March 12, 2004
概括
研究人员合成了威尔金森催化剂的类型. 这种新化合物[P3RhF]意外地激活了甲中的C-Cl键,这是有机金属化学的重大进步.
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.
- 化学 的化学
背景情况:
- 威尔金森的催化剂是各种有机转化的一种成熟的同质催化剂.
- 化 (C-Cl) 键的惰性在合成化学中是一个挑战.
- 金属化物复合物由于其独特的反应模式而引起人们的兴趣.
研究的目的:
- 为了合成和表征威尔金森催化剂的类型,[(Ph3P) 3RhF] (1).
- 为了研究化合物1的反应性,特别是对惰性C-Cl键的反应性.
- 阐明由化合物1激活新型Ph-Cl键的机制.
主要方法:
- 类同类物[(Ph3P) 3RhF] (1) 的合成.
- 使用光谱和晶体学技术对化合物1的完整表征.
- 涉及非活性化和化合物1的反应性研究.
主要成果:
- 类同类物[{Ph3P) 3RhF] (1) 已成功合成和表征.
- 化合物1表现出类似于威尔金森催化剂的溶液行为和固态几何.
- 化合物1对非激活的甲的C-Cl键表现出前所未有的反应性.
- 激活机制涉及转移到素连接体和转移到Rh,形成一个sigma-phenylrhodium中间体.
结论:
- 威尔金森催化剂的类比体现出独特的反应性,使得惰性化键的激活成为可能.
- 这一发现为催化C-Cl键的功能化开辟了新的途径.
- 拟议的机制突出显示了激活过程中的新联体和金属转化.
相关概念视频
Aldehydes and Ketones to Alkenes: Wittig Reaction Overview
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ortho–para-Directing Deactivators: Halogens
Halogens are ortho–para directors. They are more electronegative than carbon. Therefore, as ring substituents, they can withdraw electrons through the inductive effect and deactivate the aromatic ring towards electrophilic substitution. Halogens also have an electron-donating resonance effect on the ring, which influences the orientation of the incoming electrophile. If an electrophile attacks at the ortho or the para position, the halogen donates electrons and stabilizes the intermediate...
Aldehydes and Ketones to Alkenes: Wittig Reaction Mechanism
The Wittig reaction, which converts aldehydes or ketones to alkenes using phosphorus ylides, proceeds through a nucleophilic addition‒elimination process.
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
Bromination and chlorination of aromatic rings by electrophilic aromatic substitution reactions are easily achieved, but fluorination and iodination are difficult to achieve. Fluorine is so reactive that its reaction with benzene is difficult to control, resulting in poor yields of monofluoroaromatic products. To address this, Selectfluor reagent is used as a fluorine source in which a fluorine atom is bonded to a positively charged nitrogen.
Cycloaddition Reactions: MO Requirements for Photochemical Activation
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