外消旋选择性对映选择性硝酮环加成反应。
Exo selective enantioselective nitrone cycloadditions.
作者信息
Sibi Mukund P, Ma Zhihua, Jasperse Craig P
机构信息
Department of Chemistry, North Dakota State University, Fargo, North Dakota 58105, USA.
出版信息
J Am Chem Soc. 2004 Jan 28;126(3):718-9. doi: 10.1021/ja039087p.
PMID:14733537
Abstract
We have developed a novel method for accessing exo adducts with high enantioselectivity in nitrone cycloadditions to enoates. Pyrazolidinones proved to be effective achiral templates in the cycloadditions, providing exo adducts typically in >15:1 selectivity and 90-98% ee. The use of Lewis acids that form square planar complexes, such as copper triflate, was important for obtaining high exo selectivity.
摘要
我们开发了一种在硝酮与烯酸酯的环加成反应中以高对映选择性获得外型加合物的新方法。吡唑烷酮在环加成反应中被证明是有效的非手性模板，通常以大于15:1的选择性和90 - 98%的对映体过量提供外型加合物。使用能形成平面正方形配合物的路易斯酸，如三氟甲磺酸铜，对于获得高外型选择性很重要。
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