Bioinspired Manganese and Iron Complexes with Tetradentate N Ligands for the Asymmetric Epoxidation of Olefins
作者:Xiaoe Wang、Chengxia Miao、Shoufeng Wang、Chungu Xia、Wei Sun
DOI:10.1002/cctc.201300102
日期:2013.8
and iron complexes with the tetradentate N ligand (1R,2R)‐N,N'‐dimethyl‐N,N'‐bis(1‐methyl‐2‐benzimidazolylmethyl)cyclohexane‐1,2‐diamine have been synthesized and characterized. The crystal structure of the manganese complex demonstrates a cis‐α configuration. Both the manganese and iron complexes are active catalysts for the asymmetric epoxidation of olefins with H2O2 as an oxidant and acetic acid as
合成了具有四齿N配体(1 R,2 R)-N,N'-二甲基-N,N'-双(1-甲基-2-苯并咪唑基甲基)环己烷-1,2-二胺的锰和铁配合物和特点。锰配合物的晶体结构表现出顺-α构型。锰和铁络合物都是用于烯烃的不对称环氧化的活性催化剂,其中H 2 O 2为氧化剂,乙酸为添加剂。在-20°C时,观察到高达96%ee的α,β-不饱和酮的环氧化。
Asymmetric Epoxidation of Olefins with Chiral Bioinspired Manganese Complexes
作者:Mei Wu、Bin Wang、Shoufeng Wang、Chungu Xia、Wei Sun
DOI:10.1021/ol901400m
日期:2009.8.20
A novel series of chiral tetradentate N4 ligands together with their manganese complexes have been designed and synthesized. With 1 mol % manganese catalyst loading, the enantioselective epoxidation of olefins proceeds with nearly full conversion and enantiomeric excess values of up to 89 % for the first time.
A novelsyntheticmethod of ketodiphenylselenonium ylide from alkynylselenonium salt is described. A reaction of alkynylselenonium salt, hydroxide ion, and aldehyde in the presence of silver triflate and triethylamine gave oxiranylketones just as a trans-isomer in moderate to good yields, whereas benzoyl aziridine derivatives were obtained from the reaction with sodium p-toluenesulfonamide instead
Manganese Catalysts with<i>C</i><sub>1</sub>-Symmetric N<sub>4</sub>Ligand for Enantioselective Epoxidation of Olefins
作者:Bin Wang、Chengxia Miao、Shoufeng Wang、Chungu Xia、Wei Sun
DOI:10.1002/chem.201103802
日期:2012.5.29
Bioinspired manganese complexes based on N4 ligands, with a more rigid, chiral diamine derived from proline and two benzimidazoles, were synthesized and applied to epoxidize olefins with hydrogen peroxide as a clean oxidant. Notably, 60–99 % isolated yields and excellent ee values (up to 95 %) were obtained by using low catalyst loadings (0.01–0.2 mol %; see scheme; F green, S yellow).
Chiral Bioinspired Non-Heme Iron Complexes for Enantioselective Epoxidation of α,β-Unsaturated Ketones
作者:Mei Wu、Cheng-Xia Miao、Shoufeng Wang、Xiaoxue Hu、Chungu Xia、Fritz E. Kühn、Wei Sun
DOI:10.1002/adsc.201100267
日期:2011.11
Chiral bioinspired iron complexes of N4 ligands based on the ethylenediamine backbone display remarkable levels of enantioselectivity for the first time in the asymmetricepoxidation of α,β-unsaturatedketones using hydrogen peroxide (up to 87% ee) or peracetic acid as oxidant, respectively. Notablely, isotopic labeling with H218O strongly demonstrated that there is a reversible water binding step
基于乙二胺骨架的N 4配体的手性生物启发铁络合物,在使用过氧化氢(最高87%ee)或过氧乙酸作为氧化剂分别对α,β-不饱和酮进行不对称环氧化时,首次显示出显着的对映选择性。。值得注意的是,用H 2 18 O进行同位素标记强烈表明,在生成重要中间体之前,存在可逆的水结合步骤。此外,复杂的[L 2的Fe(III)2(μ-O)(μ-CH 3 CO 2)] 3+HR-MS鉴定出通常源自LFe(IV)O物种的衰变或许多铁配合物的热力学阱。此外,提出了可能的机理,LFe(V)O可能是催化体系中的主要活性中间体。