Highly Enantioselective Epoxidation of α,β-Unsaturated Ketones Catalyzed by Rare-Earth Amides [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 with Phenoxy-Functionalized Chiral Prolinols
摘要:
A simple and efficient catalytic enantioselective epoxidation of alpha,beta-unsaturated ketones has been successfully developed, which was catalyzed by rare-earth metal amides [(Me3Si)(2)N](3)RE(mu-Cl)Li(THF)(3) (RE = Yb (1), La (2), Sm (3), Y (4), Lu (5)) in the presence of phenoxy-functionalized chiral prolinols at room temperature using tert-butylhydroperoxide (TBHP) as the oxidant. The combination of an Yb-based amide 1 and a chiral proligand (S)-2,4-di-tert-butyl-6-((2-(hydroxydiphenylmethyl)pyrrolidin-1-yl)methyl)phenol) performed very well, and both the yields and the enantiomeric excess of the chiral epoxides reached up to 99% and 99% ee.
Highly Enantioselective Epoxidation of α,β-Unsaturated Ketones Catalyzed by Rare-Earth Amides [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 with Phenoxy-Functionalized Chiral Prolinols
摘要:
A simple and efficient catalytic enantioselective epoxidation of alpha,beta-unsaturated ketones has been successfully developed, which was catalyzed by rare-earth metal amides [(Me3Si)(2)N](3)RE(mu-Cl)Li(THF)(3) (RE = Yb (1), La (2), Sm (3), Y (4), Lu (5)) in the presence of phenoxy-functionalized chiral prolinols at room temperature using tert-butylhydroperoxide (TBHP) as the oxidant. The combination of an Yb-based amide 1 and a chiral proligand (S)-2,4-di-tert-butyl-6-((2-(hydroxydiphenylmethyl)pyrrolidin-1-yl)methyl)phenol) performed very well, and both the yields and the enantiomeric excess of the chiral epoxides reached up to 99% and 99% ee.
Asymmetric Epoxidation of Unsaturated Ketones Catalyzed by Heterobimetallic Rare Earth–Lithium Complexes Bearing Phenoxy-Functionalized Chiral Diphenylprolinolate Ligand
作者:Qinqin Qian、Yufang Tan、Bei Zhao、Tao Feng、Qi Shen、Yingming Yao
DOI:10.1021/ol5020398
日期:2014.9.5
Four novel heterobimetalliccomplexes [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
四种新型双核配合物[REL 2 ] [(THF)3李] 2(μ-Cl)的}通过手性苯氧基官能化prolinolate稳定(RE =镱(1),Y(2),SM(3),钕(4),H 2 L =(小号)-2,4-二-叔已经合成并表征了丁基-6-[[[2-(羟基二苯基甲基)吡咯烷-1-基]甲基]苯酚。这些容易获得的络合物在催化α,β-不饱和酮的环氧化中具有高活性,而对映选择性根据稀土中心的离子半径而变化。在10 mol%的1存在下,使用TBHP作为氧化剂,在0°C于80→99%ee下,将一系列查尔酮衍生物转化为手性环氧化物。
Asymmetric Michael addition of malonates to unsaturated ketones catalyzed by rare earth metal complexes bearing phenoxy functionalized chiral diphenylprolinolate ligands
作者:Qinqin Qian、Wenguo Zhu、Chengrong Lu、Bei Zhao、Yingming Yao
DOI:10.1016/j.tetasy.2016.07.014
日期:2016.10
A simple, efficient catalytic asymmetric Michael addition of malonates to unsaturated ketones has been successfully developed. This process was promoted by rare earth metal complexes 1-4 bearing a chiral phenoxy functionalized prolinol ligand at room temperature [(LRE)-R-1((LH)-H-1) (H2L1 = (S)-2,4-di-tert-butyl-6-(2-(hydroxydiphenylmethyl)pyrrolidin-1-yl)methyl)phenol, RE = Yb 1, Y 2, Sc 3 and (LSc)-Sc-2((LH)-H-2) 4 (H2L2 = (S)-2,4-di-dimethylbenzy1-6-(2-(hydroxydiphenylmethyl)-pyrrolidin-1-yl)methyl)phenol)]. Complex 3 was the best catalyst in the transformation and the products were obtained in,up to 99% yield and with 90% ee. In addition, the molecular structures of the catalysts were well characterized, including X-ray determination of complex 3. (C) 2016 Elsevier Ltd. All rights reserved.