Application of a chiral copper-1,1-bis{2-[(4S)-tert-butyl-oxazolinyl]}cyclopropane catalyst for asymmetric cyclopropanation of styrene
Application of a chiral copper-1,1-bis{2-[(4S)-tert-butyl-oxazolinyl]}cyclopropane catalyst for asymmetric cyclopropanation of styrene
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DOI：
10.1016/j.tetlet.2005.11.086
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发表时间：
2006-01-23
影响因子：
1.8
通讯作者：
Yamamoto, Y
中科院分区：
文献类型：
--
作者：
Itagaki, M;Yamamoto, Y
研究了铜催化重氮乙酸乙酯与苯乙烯不对称环丙化反应中双恶唑啉配体上桥基和5位的结构效应。与先前报道的最佳配体2，2-双(2-[(4S)-叔丁基恶唑基])丙烷(反式/顺式=75/25，反式产物99.0%ee)相比，1，1-双(2-[(4S)-叔丁基恶唑基]}环丙烷配体的立体选择性显著提高(反式/顺式=84/16，反式产物为99.9%ee)。(C)2005爱思唯尔有限公司。保留所有权利。
The structural effects of the bridge moiety and 5-position on bisoxazoline ligands were studied for the copper-catalyzed asymmetric cyclopropanation of styrene with ethyl diazoacetate. The 1,1-bis{2-[(4S)-tert-butyloxazolinyl]} cyclopropane ligand showed a remarkable enhancement in the stereoselectivities (trans/cis = 84/16, > 99.9% ee for the trans product) compared with he previously reported best ligand, 2,2-bis(2-[(4S)-tert-butyloxazolinyl]) propane (trans/cis=75/25, 99.0% ee for the trans product). (c) 2005 Elsevier Ltd. All rights reserved.