Asymmetric Michael addition of nitroalkanes to prochiral acceptors catalyzed by proline rubidium salts
作者:Masahiko Yamaguchi、Yoshihiro Igarashi、Ravinder S Reddy、Tai Shiraishi、Masahiro Hirama
DOI:10.1016/s0040-4020(97)00379-7
日期:1997.8
Proline rubidium salts catalyze the asymmetric Michael addition of nitroalkanes to prochiral acceptors. When (2S)-L-prolines were used, acyclic (E)-enones gave (S)-adducts and cyclic (Z)-enones gave (R)-adducts predominantly. Enantiomeric excesses exceeding 80% were attained in some reactions of secondary nitroalkanes. Primary nitroalkanes gave mixtures of diastereomers which possess the same configuration
脯氨酸rub盐催化硝基链烷烃向手性受体的不对称迈克尔加成反应。当使用(2S)-L-脯氨酸时,非环状(E)-烯酮主要产生(S)-加合物,而环状(Z)-烯酮主要产生(R)-加合物。在仲硝基烷烃的某些反应中,对映体过量超过80%。伯硝基烷烃生成非对映异构体的混合物,该混合物在β-碳原子上具有相同的构型。加合物的硝基可以被Bu 3取代为氢SnH减少。总体转化等同于烯酮的不对称β-烷基化。反应中也可以使用官能化的硝基烷烃,例如硝基醇,硝基酯和硝基烯烃。