Sibi Mukund P, Ma Zhihua, Jasperse Craig P
Department of Chemistry, North Dakota State University, Fargo, North Dakota 58105, USA.
J Am Chem Soc. 2005 Apr 27;127(16):5764-5. doi: 10.1021/ja0421497.
In this paper, we demonstrate the first examples of chiral Lewis acid catalysis in the formation of tetrahydro-1,2-oxazines with very high enantioselectivity starting with diactivated cyclopropanes and nitrones (>90% yields and ee). Reactions with racemic substituted cyclopropanes provide approximately 1:1 diastereomeric tetrahydro-1,2-oxazine products with high enantioselectivity. Mechanistic information for the formation of the tetrahydro-1,2-oxazines is also detailed.
在本文中，我们展示了手性路易斯酸催化的首个实例，即从双活化环丙烷和硝酮开始，以非常高的对映选择性形成四氢-1,2-恶嗪（产率和对映体过量值>90%）。外消旋取代环丙烷的反应提供了具有高对映选择性的大约1:1非对映异构四氢-1,2-恶嗪产物。还详细介绍了四氢-1,2-恶嗪形成的机理信息。
