Asymmetric Epoxidation of Unsaturated Ketones Catalyzed by Heterobimetallic Rare Earth鈥揕ithium Complexes Bearing Phenoxy-Functionalized Chiral Diphenylprolinolate Ligand

详细信息    查看全文

• 作者：Qinqin Qian ; Yufang Tan ; Bei Zhao ; Tao Feng ; Qi Shen ; Yingming Yao
• 刊名：Organic Letters
• 出版年：2014
• 出版时间：September 5, 2014
• 年：2014
• 卷：16
• 期：17
• 页码：4516-4519
• 全文大小：339K
• ISSN：1523-7052

文摘

Four novel heterobimetallic complexes [REL₂]{[(THF)₃Li]₂(渭-Cl)} stabilized by chiral phenoxy-functionalized prolinolate (RE = Yb (1), Y (2), Sm (3), Nd (4), H₂L = (S)-2,4-di-tert-butyl-6-[[2-(hydroxydiphenylmethyl)pyrrolidin-1-yl]methyl]phenol have been synthesized and characterized. These readily available complexes are highly active in catalyzing the epoxidation of 伪,尾-unsaturated ketones, while the enantioselectivity varies according to the ionic radii of the rare earth center. A series of chalcone derivatives were converted to chiral epoxides in 80 鈫?99% ee at 0 掳C using TBHP as the oxidant in the presence of 10 mol % of 1.