使用La-BINOL-triphenylarsine氧化物复合物对的催化不对称环氧化:对不对称催化剂的结构性确定
T Nemoto1, T Ohshima, K Yamaguchi
1Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Journal of the American Chemical Society
|July 18, 2001
概括
一种新型的-BINOL-triphenylarsine氧化物复合物有效地催化了enones的不对称环氧化. 这种方法产生具有高产量和选择性的环氧基,为催化机制提供了洞察力.
科学领域:
- 有机金属化学 有机金属化学
- 不对称的催化剂.
- 有机合成 有机合成
背景情况:
- 酶子环氧化是有机合成中至关重要的转化.
- 开发高效和选择性的不对称环氧化催化剂仍然是一个关键的挑战.
- 基于兰类的催化剂具有独特的易斯酸性和协调性质.
研究的目的:
- 用一种新的La-BINOL-Ph(3) As=O复合体来描述子的催化不对称环氧化.
- 阐明催化系统的结构和活性物种.
- 提出一个反应机制,并了解异氧化的作用.
主要方法:
- 制备La-BINOL-Ph ((3) As=O复合物从 (III) 异氧化物,BINOL和trifenylarsine氧化物中.
- 使用1-5mol%的催化剂,对各种异离子进行催化不对称的环氧化.
- 使用X射线晶体结构分析进行结构性表征.
主要成果:
- 催化剂系统有效地环氧化了一系列的恩,包括二烯和cis-enones.
- 获得了高产量 (高达99%) 和优异的抗选择性 (高达99% ee).
- 确定了活性La-BINOL-Ph(3) As=O复合物的结构,这代表了对无金属兰他诺化物-BINOL复合物的第一个X射线分析.
结论:
- 该La-BINOL-Ph(3)As=O复合体是对不对称的ENON环氧化的一种高度有效的催化剂.
- 这项研究提供了机理性的见解,包括异体体复合体形成在不对称放大中的作用.
- 兰异氧化物加快了反应的速度,同时保持了高的酶选择性.
相关概念视频
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Selection Rules: Photochemical Activation
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