Catalytic asymmetric cycloaddition of anthrone with N-alkyl- and N-arylmaleimides with various substituents in the aromatic ring was carried out in the presence of C2-chiral pyrrolidines to afford chiral, non-racemic [4 + 2] adducts. Among them, good catalytic activity was observed with the pyrrolidines with a N-(4-pyridyl)methyl group 1h, which was discussed from the viewpoint of conformational analysis. The best stereoselectivity of 87% ee was attained when the reaction of N-(2-tert-butylphenyl)maleimide 4j and anthrone was promoted with 1h.
在 C2 手性
吡咯烷存在下,
蒽酮与芳香环上具有不同取代基的 N-烷基和 N-芳基马来
酰亚胺进行了催化不对称环加成反应,得到了手性非外消旋 [4 + 2] 加合物。其中,带有 N-(4-
吡啶基)甲基的
吡咯烷类化合物 1h 具有良好的催化活性,并从构象分析的角度对其进行了讨论。用 1h 促进 N-(2-
叔丁基苯基)马来
酰亚胺 4j 和
蒽酮的反应,可获得 87%ee 的最佳立体选择性。