一个简单的催化剂,具有单一的分离立体中心,用于酶选择性基氨基化. 从机械分析中选择催化剂
Andreas Leitner1, Shashank Shekhar, Mark J Pouy
1Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520-8107, USA.
Journal of the American Chemical Society
|November 3, 2005
概括
这项研究表明,具有单个性元素的更简单的胺联体可以有效地控制催化氨化反应中的立体选择性,简化了对不对称合成的催化剂设计.
科学领域:
- 有机金属化学 有机金属化学
- 不对称的催化剂.
- 连接物设计 连接物设计
背景情况:
- 催化氨化碳酸是有机合成中的关键反应.
- 胺酸配体对于控制这些反应中的立体选择性至关重要.
- 了解连接体立体化学和催化性能之间的关系对于开发高效的催化剂至关重要.
研究的目的:
- 研究胺联体中的立体化学变异对催化氨基化的立体选择性的影响.
- 确定这种催化系统中有效的立体控制的最小结构要求.
- 探索在不对称氨基化中简化连接体设计的潜力.
主要方法:
- 合成和表征各种含有系统变化的立体化学元素的胺酸联体.
- 催化氨基化反应使用这些配体与酸碳酸盐.
- 分析反应速率,区域选择性和反选择性.
- 绝对产品立体化学的确定.
主要成果:
- 催化剂激活涉及形成一个带有特定性元素的循环金属复合体.
- 用阿基拉群替换一个远端性替代剂并没有显著改变催化性能.
- 双立体干体表现出不同的循环金属化率.
- 一个带有双酸盐核心和单个性乙基组的简化连接体产生了与更复杂的连接体相比较的速率,区域选择性和反选择性.
- 主要的反体是由含有双酸盐的催化剂的特定体形成的.
结论:
- 催化氨基化的立体选择性主要是由胺联体中的特定性元素决定的.
- 简化的胺酸联体,即使只有一种奇拉替代剂,也可以达到高水平的立体控制.
- 这一发现促进了对不对称氨基化的更容易获得和更有效的催化剂的开发.
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