into an epoxide was developed using an opticallyactive ketoiminatocobalt(II) complex as a chiral Lewis acid. In the presence of a catalytic amount of the cobalt complex and amine base, enantioselective CO 2 fixation with an epoxide proceeded with kineticresolution to afford the corresponding carbonate along with unreacted epoxide, both of which were opticallyactive. To improve their enantioselectivities
使用光学活性的酮亚氨基钴 (II) 配合物作为手性路易斯酸开发了 CO 2 对映选择性化学固定到环氧化物中。在催化量的钴络合物和胺碱的存在下,与环氧化物的对映选择性 CO 2 固定进行动力学拆分,得到相应的碳酸盐和未反应的环氧化物,两者都是光学活性的。为了提高它们的对映选择性,研究了钴配合物和胺碱的配体结构。因此,优化的催化体系成功地应用于各种环氧化物,以获得相应的光学活性环状碳酸酯,并以良好的对映选择性回收环氧化物。
Chiral Macrocyclic Organocatalysts for Kinetic Resolution of Disubstituted Epoxides with Carbon Dioxide
Among chiral macrocycles 1 synthesized, 1m with the 3,5-bis(trifluoromethyl)phenylethynyl group was the best organocatalyst for the enantioselective synthesis of cyclic carbonates from disubstituted or monosubstituted epoxides and CO2. The X-ray crystal structure of 1m revealed a well-defined chiral cavity with multiple hydrogen-bonding sites that is suitable for the enantioselective activation of
Chiral Bifunctional Metalloporphyrin Catalysts for Kinetic Resolution of Epoxides with Carbon Dioxide
作者:Chihiro Maeda、Mayato Mitsuzane、Tadashi Ema
DOI:10.1021/acs.orglett.9b00447
日期:2019.3.15
triazolium halide units were synthesized as bifunctional catalysts for kinetic resolution of epoxides with CO2. Several catalysts were screened by changing the linker length and nucleophilic counteranions, and the optimized catalyst accelerated the enantioselective reaction at ambient temperature to produce optically active cyclic carbonates and epoxides.
Synthesis and enzymatic resolution of racemic 2,3-epoxy propyl esters obtained from glycerol
作者:Yara Jaqueline Kerber Araujo、Naga Prasad Avvari、Derisvaldo Rosa Paiva、Dênis Pires de Lima、Adilson Beatriz
DOI:10.1016/j.tetlet.2015.02.046
日期:2015.3
A method is described for the synthesis of (+/-)-2,3-epoxy propyl esters from glycerol, involving reaction of epichlorohydrin with sodium or potassium salts of carboxylic acids in the presence of TBAB as catalyst, with moderate to excellent yields. Kinetic resolution of glycidyl butyrate by lipase of Thermomyces lanuginosa has been achieved with remarkable enantiomeric excess (ee >99%) using 1,4-dioxane as a co-solvent in pure buffer solution (30 and 50 degrees C, pH = 7.0). (C) 2015 Elsevier Ltd. All rights reserved.
Novel Synthesis And Enzymatic Resolution of (±) -2,3 - Epoxy Propyl Esters
作者:Ranjeet V. Nair、Prashant N. Patil、Manikrao M. Salunkhe
DOI:10.1080/00397919908086413
日期:1999.8.1
A novel method of synthesizing glycidyl esters (+/-)-2,3-epoxy propyl esters has been developed involving reaction of epichlorohydrin with sodium salt of carboxylic acids in the presence of 15-crown-5 as catalyst with excellent yields. Enzymatic resolution of these glycidyl esters by lipasePS-C has been achieved with remarkable substrate selectivity.