蓝稳定格里纳德试剂的立体化学反转:以太溶剂结构和度的显著影响
Ming Gao1, Neeraj N Patwardhan, Paul R Carlier
1Department of Chemistry, Virginia Tech , Blacksburg, Virginia 24061, United States.
Journal of the American Chemical Society
|August 28, 2013
概括
溶剂的标识和度显著影响了基拉尔格林纳德试剂的配置稳定性. 与乙烯相比,THF和2-MeTHF等以太溶剂加快了表皮化速率,影响了不对称的合成结果.
科学领域:
- 有机金属化学 有机金属化学
- 不对称的合成方法
- 立体化学是一种立体化学.
背景情况:
- 体有机金属试剂对于不对称合成至关重要.
- 这些试剂的结构稳定性对于成功的反应至关重要.
- 了解影响稳定性的因素,如溶剂效应,是关键.
研究的目的:
- 为了研究一种性格里格纳德试剂的表皮化.
- 为了确定以太溶剂对配置稳定性的影响.
- 量化溶剂标识和度对表皮化率的影响.
主要方法:
- 一个胺的Mg/Br交换形成一个合的格林纳德试剂.
- 在低温 (195 K) 下测量表皮化速率常数 (k(tc)) .
- 随着时间的推移,对化产物二聚体比率的分析.
- 用各种乙醇溶剂和烯进行结石测量和度依赖性研究.
主要成果:
- /交换显示在二甲基乙醇 (Et2O) 中的保留率高,但在2-MeTHF和THF 中的保留率较低.
- 溶剂的表皮化速率有很大差异:Et2O的26倍,2-MeTHF的800倍,THF的1300倍,而烯的0.12M Et2O是0.12M Et2O.
- 格里纳德试剂可能存在于Et2O中的异构聚物,而表皮化不需要脱聚.
- 分析表明,在限制速率的离子对分离之前,快速增量溶解.
结论:
- 溶剂的标识和度深深地影响了基拉尔格林纳德试剂的配置稳定性.
- 该研究提供了溶剂配体捕获 (-13 ± 3 eu) 的估计性成本.
- 提出了一个潜在的"离子导向巡回"表皮化途径,并得到了计算支持.
相关概念视频
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