非C2对称的化催化剂,用于高效的反选择性分子内C3化
Zijun Zhou1, Shuming Chen2, Yubiao Hong1
1Fachbereich Chemie , Philipps-Universität Marburg , Hans-Meerwein-Strasse 4 , 35043 Marburg , Germany.
Journal of the American Chemical Society
|November 22, 2019
概括
具有远程N-异环碳联体的新型性催化剂可实现高效的分子内C ((sp3) -H化. 非C2对称的催化剂产生具有高反选择性的奇拉性玛乳,其性能优于C2对称的催化剂.
科学领域:
- 有机金属化学
- 催化剂
- 不对称的合成
背景情况:
- 催化剂在有机合成中至关重要.
- 基拉尔催化剂可以实现反选择性转化.
- 在催化过程中,N-异环碳酸 (NHC) 是多用途的配体.
研究的目的:
- 引入一种新的化催化剂.
- 研究这些复合体在分子内C ((sp3) -H化中的催化活性.
- 了解金属中心立体化学在催化结果中的作用.
主要方法:
- 合成与pyridylidene远程N- heterocyclic carbene (rNHC) 配合物的性复合物.
- 1,4,2-dioxazol-5-ones的分子内C(sp3) -H化催化试验
- 使用奇拉色谱测定等离子比率.
- 密度函数理论 (DFT) 计算以阐明反应机制.
主要成果:
- 一种由7-甲基-1,7-乙烯基环环合成的新型性催化剂.
- 非C2对称的化复合物对分子内C ((sp3) -H化具有很高的催化活性,产生高达99:1的化.
- 低于0.005%的催化剂负荷是有效的 (高达11,200).
- 主要发生了不必要的库尔蒂乌斯型重组.
- DFT计算揭示了非C2对称催化剂的高反应率的起源.
结论:
- 相对金属中心立体化学对于在C ((sp3) -H化中实现高反选择性至关重要.
- 非C2对称的性催化剂为合成性-乳酸提供了前所未有的效率.
- 开发的催化系统为不对称合成提供了有价值的工具.
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