title: Asymmetric epoxidation of unsaturated ketones catalyzed by heterobimetallic rare earth-lithium complexes bearing phenoxy-functionalized chiral diphenylprolinolate ligand.
abstract: Four novel heterobimetallic complexes [REL2]{[(THF)3Li]2(μ-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 α,β-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 → 99% ee at 0 °C using TBHP as the oxidant in the presence of 10 mol % of 1.
authors.affiliation: Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Dushu Lake Campus, Soochow University , Suzhou 215123, China.
authors.forename: Qinqin
authors.initials: Q
authors.lastname: Qian
authors.forename: Yufang
authors.initials: Y
authors.lastname: Tan
authors.forename: Bei
authors.initials: B
authors.lastname: Zhao
authors.forename: Tao
authors.initials: T
authors.lastname: Feng
authors.forename: Qi
authors.initials: Q
authors.lastname: Shen
authors.forename: Yingming
authors.initials: Y
authors.lastname: Yao
mesh_terms: D002384:Catalysis; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry; D004852:Epoxy Compounds / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D008024:Ligands; D008094:Lithium / Q000737:chemistry*; D008674:Metals, Rare Earth; D015394:Molecular Structure; D011392:Proline / Q000031:analogs & derivatives* / Q000737:chemistry*; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D004852:Epoxy Compounds; D007659:Ketones; D008024:Ligands; D008674:Metals, Rare Earth; D011392:Proline; D008094:Lithium; D015018:Ytterbium