Highly Asymmetric Intramolecular Cyclopropanation of Acceptor-Substituted Diazoacetates by Co(II)-Based Metalloradical Catalysis: Iterative Approach for Development of New-Generation Catalysts
作者:Xue Xu、Hongjian Lu、Joshua V. Ruppel、Xin Cui、Silke Lopez de Mesa、Lukasz Wojtas、X. Peter Zhang
DOI:10.1021/ja2062506
日期:2011.10.5
Co(II)-catalyzed asymmetric cyclopropanation of alkenes. The Co(II) complex of 3,5-Di(t)Bu-QingPhyrin, [Co(P2)], has proved to be a general and effective catalyst for asymmetric intramolecular cyclopropanation of various allylic diazoacetates (especially including those with α-acceptor substituents) in high yields with excellent stereoselectivities. The [Co(P2)]-based intramolecular metalloradical cyclopropanation
3,5-Di(t)Bu-QingPhyrin,一种新的 D(2)-对称手性卟啉,衍生自含有两个连续立体中心的手性环丙烷甲酰胺,已使用基于 Co(II) 催化不对称环丙烷化的迭代方法开发烯烃。3,5-Di(t)Bu-QingPhyrin 的 Co(II) 配合物 [Co(P2)] 已被证明是各种烯丙基重氮乙酸酯(尤其包括具有 α-受体取代基)以高产率和优异的立体选择性。基于 [Co(P2)] 的分子内金属基环丙烷化可以方便地获得具有高对映体纯度的高密度官能化 3-oxabicyclo[3.1.0]hexan-2-one 衍生物。