替代酸的形成结构和速率研究
Jason C Riggs1, Antonio Ramirez, Matthew E Cremeens
1Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA.
Journal of the American Chemical Society
|February 26, 2008
概括
溶剂的选择显著影响从光烯形成. 了解这些溶剂效应对于控制有机金属反应中的区域选择性至关重要.
科学领域:
- 有机化学 有机化学
- 有机金属化学 有机金属化学
背景情况:
- 从2-haloaryllithiums中形成类是关键的合成步骤.
- 已知这些消除中的区域选择性受反应条件的影响.
研究的目的:
- 为了研究溶剂依赖的区域选择性,在消除阶段形成3-替代和3,6-非替代.
- 阐明控制化去除的机制性途径.
主要方法:
- 核磁共振 (NMR) 光谱 (6Li和13C) 用于研究四基 (THF) 中的单体物种.
- 密度函数理论 (DFT) 计算研究以建模解和过渡状态.
- 动力学研究以确定反应速率和反应途径.
主要成果:
- 在THF中以单体的形式存在具有在6位的电子提取组的2-Haloaryllithiums.
- DFT计算表明涉及三酸盐中间体.
- F的消除通过THF离合途径进行,而LiCl的消除通过非离合途径发生.
- 从2-chloro-6-fluorophenyllithium中消除LiCl和LiF,由于相互竞争的途径,显示出明显的溶剂依赖的区域选择性.
结论:
- 形成的区域选择性高度依赖于离开化物 (F与Cl) 的性质和溶剂相互作用.
- 在THF中的单质烯酸通过化物与溶剂和离子相互作用所决定的途径消除化物.
相关概念视频
Structure of Benzene: Kekulé Model
In 1865, August Kekule suggested the structure of benzene according to the structural theory of organic chemistry based on the three assertions—formula of benzene is C6H6, all the hydrogens of benzene are equivalent, and each carbon must have four bonds due to its tetravalency.
He proposed that benzene has a cyclic structure of six carbon atoms attached to one hydrogen atom each, with three alternating pi bonds.
He proposed that benzene has a cyclic structure of six carbon atoms attached to one hydrogen atom each, with three alternating pi bonds.
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For disubstituted benzene derivatives, with two groups attached to the benzene ring, three constitutional isomers are possible. For example, consider dimethyl benzene, often called xylene, where the second methyl group can be substituted at the second, third, or fourth carbon. The relative position of the substituents is represented by prefixes ortho, meta, or...
For disubstituted benzene derivatives, with two groups attached to the benzene ring, three constitutional isomers are possible. For example, consider dimethyl benzene, often called xylene, where the second methyl group can be substituted at the second, third, or fourth carbon. The relative position of the substituents is represented by prefixes ortho, meta, or...


