素稳定转化催化剂的一般分解途径:路易斯捐赠者加速甲基抽象
William L McClennan1, Stephanie A Rufh1, Justin A M Lummiss1
1Department of Chemistry and Centre for Catalysis Research & Innovation, University of Ottawa , Ottawa, Ontario K1N 6N5, Canada.
无菌可获得的易斯供体加速了格拉布斯级转化催化剂的分解. 即使是微弱的供体也会降低催化剂的生产力,这凸显了供体溶剂中素稳定催化剂的风险.
科学领域:
- 有机金属化学
- 催化剂
- 有机合成
背景情况:
- 格拉布斯类催化剂对于氨酸转化反应至关重要.
- 催化剂分解途径限制了效率和适用性.
- 了解分解机制对于催化剂的设计和应用至关重要.
研究的目的:
- 调查易斯捐赠者对格拉布斯类转化催化剂分解的影响.
- 确定活性物种和分解产品.
- 阐明由供体诱导的催化剂降解的机制.
主要方法:
- 基和基格鲁布斯级预催化剂的合成和表征.
- 在现场监测各种路易斯捐赠物 (例如,pyridine,THF,DMSO) 的催化剂分解.
- 用光谱分析 (例如31P NMR) 来识别中间体和分解产物.
主要成果:
- 无菌可获得的易斯供体显著加速催化剂的分解.
- 皮里丁通过甲基提取快速分解特定的格鲁布斯类催化剂 (Ru-4a,Ru-4b).
- 较弱的供体 (THF,MeCN,DMSO,MeOH,H2O) 也促进了分解,随着供体度的增加,其速度也在增加.
- 含有素的碎片[MePCy3]Cl (A) 是主要的分解产物.
结论:
- 路易斯的捐赠者,即使是弱者,也会严重降低格拉布斯级催化剂的性能.
- 这种分解途径涉及甲基提取,形成稳定的盐.
- 在富含供体的环境中使用氨酸稳定转化催化剂时应谨慎使用.
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