Silicon-based Lewis acid assisted cinchona alkaloid catalysis: highly enantioselective aza-Michael reaction under solvent-free conditions.
Silicon-based Lewis acid assisted cinchona alkaloid catalysis: highly enantioselective aza-Michael reaction under solvent-free conditions.
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DOI：
10.1021/ol202803b
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发表时间：
2011-11
期刊：
影响因子：
5.2
通讯作者：
Huameng Yang;Li Li-Li;Fei Li;K. Jiang;Jun‐Yan Shang;G. Lai;Li‐Wen Xu
中科院分区：
文献类型：
--
作者：
Huameng Yang;Li Li-Li;Fei Li;K. Jiang;Jun‐Yan Shang;G. Lai;Li‐Wen Xu
该研究表明，非手性硅基刘易斯酸和手性刘易斯碱的组合，如三甲基碘硅烷（TMSI）和辛可宁，在无溶剂条件下生成了高度对映选择性的催化剂体系，得到芳香族β-氨基酮，含量高达>99% ee.机理研究表明，增强的不对称诱导可能是由于查尔酮的羰基部分与辛可宁和硅基刘易斯酸在氮杂-迈克尔反应中的反应。
The study showed that a combination of an achiral silicon-based Lewis acid and chiral Lewis base, such as iodotrimethylsilane (TMSI) and cinchonine, generated a highly enantioselective catalyst system under solvent-free conditions which gave aromatic β-amino ketones with up to >99% ee. Mechanistic studies demonstrate the enhanced asymmetric induction may be due to the combined and competitive activation of a carbonyl moiety of chalcone with cinchonine and the silicon-based Lewis acid in the aza-Michael reaction.