Mn-Salen Catalyzed Asymmetric Oxidation of Simple Olefins and Sulfides
Mn-Salen Catalyzed Asymmetric Oxidation of Simple Olefins and Sulfides
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Mn-Salen 催化简单烯烃和硫化物的不对称氧化
DOI：
10.1002/chin.199621263
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
T. Katsuki*
中科院分区：
文献类型：
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作者：
T. Katsuki*
在所研究的几种Mn-salen型催化剂中，发现合理设计的Mnsalen催化剂（14）对于简单烯烃的不对称环氧化是最有效的，特别是与芳基、烯基和炔基共轭的顺式二取代和三取代烯烃。该反应的不对称诱导机制已被很好地合理化的建议，烯烃接近氧代金属从侧面上得到金属氧杂环丁烷中间体，其中空间和电子之间的排斥的salen配体和烯属取代基决定了传入的烯烃的取向，中间体转化为环氧化物通过自由基中间体。还发现Mn-salen催化剂有效催化硫化物的不对称氧化（21）。
Among the several Mn-salen type catalysts studied, a rationally designed Mnsalen catalyst (14) was found to be the most effective for asymmetric epoxidation of simple olefins, especially cis-disubstituted and trisubstituted olefins conjugated with aryl, alkenyl and alkynyl groups. The mechanism of asymmetrc-inducition of this reaction has been well rationalized by the proposal that olefins approach oxo-metal from the side-on to give a metallaoxetane intermediate, wherein steric and electronic repulsions between the salen ligand and the olefinic substituent dictate the orientation of the incoming olefins and, the intermediate is transformed into epoxides via a radical intermediate. Asymmetric oxidation of sulfides was also found to be effectively catalyzed by Mn-salen catalyst (21).