双分子合作为快速启动的氨酸转化催化剂的分解载体
Gwendolyn A Bailey1, Marco Foscato2, Carolyn S Higman1
1Center for Catalysis Research and Innovation, and Department of Chemistry and Biomolecular Sciences , University of Ottawa , Ottawa , ON , Canada K1N 6N5.
Journal of the American Chemical Society
|April 14, 2018
概括
快速启动的,无的催化剂通过甲基合分解,而不仅仅是消除. 这种双分子合途径对于理解这些重要的烯转化催化剂的不稳定性至关重要.
科学领域:
- 有机金属化学
- 催化剂
- 有机合成
背景情况:
- 氨酸转化是有机合成中的一个重要反应,使得碳-碳双键的形成成为可能.
- 快速启动,无的催化剂在反应性方面具有优势,但可能会遭受快速分解.
- 之前的研究发现,从金属环中介物中消除是主要的分解途径.
研究的目的:
- 为了研究各种快速启动的无基催化剂的分解途径.
- 将催化剂启动速度与其分解机制相关联.
- 提供超出β消除的替代分解途径的直接证据.
主要方法:
- 一系列无素催化剂的合成和表征,包括霍维达 (HII),格雷拉 (nG),皮尔斯 (PII),格拉布斯III (GIII) 和迪安林 (DA) 催化剂.
- 动力学研究和分子级计算分析以探测分解机制.
- 对暂时稳定的甲基中间体进行了受控分解实验.
主要成果:
- 对于HII,GN,PII和DA催化剂,β消除只能产生25-40%的,而对于GIII则没有.
- 通过二分子合甲基中间体 (Ru-1) 确定了竞争的分解途径.
- 从稳定的甲基添加物的分解中获得了甲基结合的直接证据.
结论:
- 双分子甲基合是甲基中间体 (Ru-1) 不稳定的重要因素.
- 这种合途径是快速启动的,无胺转化催化剂的主要分解途径.
- 了解这些分解途径对于设计更稳定,更有效的转化催化剂至关重要.
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