- Engineering a homochiral metal-organic framework based on an amino acid for enantioselective separation
-
A chiral metal-organic framework possessing an open amphiphilic channel is constructed from a dicarboxylate ligand derived from an amino acid and is shown to be an efficient and recyclable chiral solid adsorbent, which is capable of separating racemic secondary alcohols, epoxides, and ibuprofen with very high enantioselectivity.
- Tang, Haitong,Yang, Keke,Wang, Kun-Yu,Meng, Qi,Wu, Fan,Fang, Yu,Wu, Xiang,Li, Yougui,Zhang, WenCheng,Luo, Yunfei,Zhu, Chengfeng,Zhou, Hong-Cai
-
p. 9016 - 9019
(2020/08/17)
-
- Chiral Bifunctional Metalloporphyrin Catalysts for Kinetic Resolution of Epoxides with Carbon Dioxide
-
Chiral binaphthyl-strapped Zn(II) porphyrins with 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.
- Maeda, Chihiro,Mitsuzane, Mayato,Ema, Tadashi
-
supporting information
p. 1853 - 1856
(2019/03/11)
-
- Enantioselective Resolution Copolymerization of Racemic Epoxides and Anhydrides: Efficient Approach for Stereoregular Polyesters and Chiral Epoxides
-
Herein we report an efficient strategy for preparing isotactic polyesters and chiral epoxides via enantioselective resolution copolymerization of racemic terminal epoxides with anhydrides, mediated by enantiopure bimetallic complexes in conjunction with a nucleophilic cocatalyst. The chirality of both the axial linker and the diamine backbones of the ligand are responsible for the chiral induction of this kinetic resolution copolymerization process. The catalyst systems exhibit exceptional levels of enantioselectivity with a kinetic resolution coefficient exceeding 300 for various racemic epoxides, affording highly isotactic copolymers (selectivity factors of more than 300) with a completely alternating structure and low polydispersity index. Most of the produced isotactic polyesters are typical semicrystalline materials with melting temperatures in the range from 77 to 160 °C.
- Li, Jie,Ren, Bai-Hao,Wan, Zhao-Qian,Chen, Shi-Yu,Liu, Ye,Ren, Wei-Min,Lu, Xiao-Bing
-
supporting information
p. 8937 - 8942
(2019/06/11)
-
- Dinuclear salen cobalt complex incorporating Y(OTf)3: enhanced enantioselectivity in the hydrolytic kinetic resolution of epoxides
-
The activation of inactive Jacobsen's chiral salen Co(ii) (salen = N,N′-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine) compound is attained by dinuclear chiral salen Co(iii)-OTf complex formation with yttrium triflate. The yttrium metal not only displays a promoting effect on electron transfer, but also assists in forming two stereocentres of a Lewis acid complex with Co(iii)-OTf. We found that the binuclear Co-complex significantly enhanced reactivity and enantioselectivity in the hydrolytic kinetic resolution of terminal epoxides compared to its analogous monomer and kinetic data are also consistent with these results.
- Patel, Deepak,Kurrey, Ganesh Ram,Shinde, Sandip S.,Kumar, Pradeep,Kim, Geon-Joong,Thakur, Santosh Singh
-
p. 82699 - 82703
(2015/10/19)
-
- Chiral nanoporous metal-metallosalen frameworks for hydrolytic kinetic resolution of epoxides
-
Chiral nanoporous metal-organic frameworks are constructed by using dicarboxyl-functionalized chiral Ni(salen) and Co(salen) ligands. The Co(salen)-based framework is shown to be an efficient and recyclable heterogeneous catalyst for hydrolytic kinetic resolution (HKR) of racemic epoxides with up to 99.5% ee. The MOF structure brings Co(salen) units into a highly dense arrangement and close proximity that enhances bimetallic cooperative interactions, leading to improved catalytic activity and enantioselectivity in HKR compared with its homogeneous analogues, especially at low catalyst/substrate ratios.
- Zhu, Chengfeng,Yuan, Guozan,Chen, Xu,Yang, Zhiwei,Cui, Yong
-
supporting information; experimental part
p. 8058 - 8061
(2012/07/14)
-
- New propranolol analogues: Binding and chiral discrimination by cellobiohydrolase Cel7A
-
Novel propranolol analogues have been designed and synthesised and their enantioselective binding to the cellulose degrading enzyme, Cel7A, has been evaluated. Affinity and enantioselectivity have been determined by capillary electrophoresis experiments. Ligands with significantly improved affinity and selectivity have been obtained and an analysis of the results has led to insights concerning the relation between the changes in ligand structure and selectivity as well as affinity to the protein. The Royal Society of Chemistry 2006.
- Fagerstroem, Alexandra,Nilsson, Mikael,Berg, Ulf,Isaksson, Roland
-
p. 3067 - 3076
(2008/02/12)
-
- Metal ion-activated molecular receptors for aromatic anions with receptor cavities formed from 1- Or 2-naphthyloxy moieties appended to cyclen
-
Studies of two newly synthesised, isomeric metal ion-activated molecular receptors, [Cd(1,4,7,10-tetrakis{(S)-(-)-2-hydroxy-3-(1′-naphthyloxy) propyl}-1,4,7,10-tetraazacyclododecane)](ClO4)2· H2O and [Cd(1,4,7,10-tetrakis {(S)-(-)-2-hydroxy-3-(2′- naphthyloxy)propyl}-1,4,7,10-tetraazacyclododecane)](ClO4) 2, show that both act as molecular receptors for the p-toluenesulfonate anion. The binding cavity depths for the two receptors were calculated from ab initio molecular modelling to be 4.81 and 7.27 A, respectively. Despite the smaller cavity depth for the first receptor, it forms the more stable inclusion complexes, as assessed by the relative magnitude of the decrease in electrical conductivity and 13C NMR spectral changes. This indicates that hydrogen bonds, from the hydroxyl hydrogen-bond donors at the base of the receptor cavity, rather than n interactions between the aromatic walls of the cavity and the included p-toluenesulfonate are principally responsible for its retention. Nonetheless, the hydrophobic character of the aromatic-binding cavity walls may play a major kinetic role in the formation of the inclusion complexes. The Royal Society of Chemistry 2003.
- Smith, Christopher B.,Buntine, Mark A.,Lincoln, Stephen F.,Wainwright, Kevin P.
-
p. 3028 - 3033
(2007/10/03)
-
- Enzyme Assisted Preparation of Enantiomerically Pure β-Adrenergic Blockers III. Optically Active Chlorohydrin Derivatives and Their Conversion
-
Optical active chlorohydrin derivatives 2a-m and 3a-m of both enantiomeric series were prepared via both enzymatic hydrolyses and acyltransfer reactions catalysed by a highly selective lipase from Pseudomonas sp..The resulting building blocks were further transformed into the corresponding β-blockers of high enantiomeric purity.
- Ader, Ulrich,Schneider, Manfred P.
-
p. 521 - 524
(2007/10/02)
-