one-pot, two-step process was disclosed for production of chiral α,β-epoxy ketonesfrom benzaldehydes and acetophenones catalyzed by imidazolium-modified poly(l-leucine). Two effective reaction systems with complementary high enantioselectivities (up to 98% ee) or satisfactory yields (up to 89%) have been developed. Importantly, the poly(aminoacid) catalyst can be easily recovered and recycled for ten
Syntheses, Structures, and Catalytic Activities of the Anionic Heterobimetallic Rare-Earth Metal Complexes Supported by Pyrrolyl-Substituted 1,2-Diimino Ligands
rare-earth metal complexes (L3)2RELi(THF)2 (RE = Pr (11), Sm(12), Eu(13)). Reactions of [(Me3Si)2N]3RE(μ-Cl)Li(THF)3 with 2 equiv of (R,R)-1,2-bis(pyrrol-2-ylmethyleneamino)cyclohexane (H2L4) also gave the heterobimetallic rare-earth metal complexes (L4)2RELi(THF)2 (Ln = Pr(14), Sm(15)). All complexes were characterized by spectroscopic methods and elemental analyses, and complexes 5–11, 13, and 14
A highly efficient catalytic kinetic resolution of 2,3-epoxy 3-aryl ketones via asymmetric ring-opening with pyrazole derivatives has been achieved by using a chiral N,N′-dioxide–Sc(iii) complex as the catalyst.
Enantioselective epoxidation of α,β-enones promoted by (1R,3S,4S)-2-azanorbornyl-3-methanol as an organocatalyst
作者:Jun Lu、Yun-He Xu、Feng Liu、Teck-Peng Loh
DOI:10.1016/j.tetlet.2008.07.175
日期:2008.10
(1R,3S,4S)-2-Azanorbornyl-3-methanol was synthesized form (R)-1-phenylethylamine and used as a catalyst for the enantioselectiveepoxidation of α,β-enones to afford the corresponding epoxides in good yields and high enantioselectivities at room temperature.
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。