Organocatalysts Promote Enantioselective 1,3-Dipolar Cycloadditions of Nitrones with 1-Cycloalkene-1-carboxaldehydes
作者:Staffan Karlsson、Hans-Erik Högberg
DOI:10.1002/ejoc.200300172
日期:2003.8
In the presence of enantiopure organocatalysts, 1-cycloalkene-1-carboxaldehydes and various nitrones furnished fused isoxazolidines. Thus, some chiral pyrrolidinium salts catalyzed the formation of such cycloadducts in high diastereo- and enantioselectivity (up to 92% ee). The predominant diastereomer, the exo one, was mostly obtained in excellent diastereoselectivity (> 99:1 dr). Furthermore, after
在对映体纯有机催化剂存在下,1-环烯烃-1-甲醛和各种硝酮提供稠合异恶唑烷。因此,一些手性吡咯烷盐以高非对映选择性和对映选择性(高达 92% ee)催化此类环加合物的形成。主要的非对映异构体,即外向异构体,主要以优异的非对映选择性 (> 99:1 dr) 获得。此外,在环加合物之一重结晶后,得到对映体纯(> 99% ee)。确定环加合物之一的绝对构型。