67843-74-7Relevant articles and documents
An Amphiphilic (salen)Co Complex – Utilizing Hydrophobic Interactions to Enhance the Efficiency of a Cooperative Catalyst
Solís-Mu?ana, Pablo,Salam, Joanne,Ren, Chloe Z.-J.,Carr, Bronte,Whitten, Andrew E.,Warr, Gregory G.,Chen, Jack L.-Y.
supporting information, p. 3207 - 3213 (2021/06/01)
An amphiphilic (salen)Co(III) complex is presented that accelerates the hydrolytic kinetic resolution (HKR) of epoxides almost 10 times faster than catalysts from commercially available sources. This was achieved by introducing hydrophobic chains that increase the rate of reaction in one of two ways – by enhancing cooperativity under homogeneous conditions, and increasing the interfacial area under biphasic reaction conditions. While numerous strategies have been employed to increase the efficiency of cooperative catalysts, the utilization of hydrophobic interactions is scarce. With the recent upsurge in green chemistry methods that conduct reactions ‘on water’ and at the oil-water interface, the introduction of hydrophobic interactions has potential to become a general strategy for enhancing the catalytic efficiency of cooperative catalytic systems. (Figure presented.).
Molecular modification of a halohydrin dehalogenase for kinetic regulation to synthesize optically pure (S)-epichlorohydrin
Zhang, Xiao-Jian,Deng, Han-Zhong,Liu, Nan,Gong, Yi-Chuan,Liu, Zhi-Qiang,Zheng, Yu-Guo
, p. 154 - 160 (2019/01/08)
Asymmetric synthesis of chiral epichlorohydrin (ECH) from 1,3-dichloro-2-propanol (1,3-DCP) using halohydrin dehalogenases (HHDHs) is of great value due to the 100% theoretical yield and high enantioselectivity. The vital problem in the asymmetric synthesis is to prepare optically pure ECH. In this study, key amino acid residues located at halide ion channels of HheC (P175S/W249P) (HheCPS) were modified to regulate the kinetic parameters. HheCPS I81W, F86N and V94R were constructed with the corresponding halide ion channels destroyed. The catalytically efficiencies (kcat/Km) of the three mutants exhibited 0.38-, 0.23- and 0.23-fold decrease toward (S)-ECH and the reverse reaction was significantly inhibited. As the results, (S)-ECH was synthesized with >99% enantiomeric excess (e.e.) and 63.42%, 67.08% and 57.01% yields, respectively, under 20 mM 1,3-DCP as substrate. To our knowledge, this is the first investigation of the molecule kinetic modification of HHDHs and also the first report for the biosynthesis of optically pure (S)-ECH from 1,3-DCP using HHDHs.
Aromatic donor-acceptor interaction promoted catalyst assemblies for hydrolytic kinetic resolution of epichlorohydrin
Blechschmidt, Daniel R.,Woodhouse, Matthew D.,Inagaki, Sebastien,Whitfield, Melita,Ogunsanya, Ayokunnumi,Yoder, Aaron,Lilly, Daniel,Heim, Eric W.,Soucie, Luke N.,Liang, Jian,Liu, Yu
supporting information, p. 172 - 180 (2019/01/04)
Three generations of Co(iii)-salen complexes containing electron-deficient aromatic moieties (acceptors) have been synthesized. When electron-rich aromatic compounds (donors) were introduced, these complexes were designed to form catalyst assemblies through aromatic donor-acceptor interaction. For all three generations of complexes, the addition of a proper donor led to higher catalytic efficiency in the hydrolytic kinetic resolution (HKR) of epichlorohydrin. The reaction rates are in the following order: Generation 3 > Generation 2 > Generation 1. The aromatic donor-acceptor interaction was verified by NMR spectroscopy and UV-vis absorption spectroscopy studies. These results demonstrated that aromatic donor-acceptor interaction can be a valuable driving force in the assembly of supramolecular catalysts.
Aromatic Donor-Acceptor Interaction-Based Co(III)-salen Self-Assemblies and Their Applications in Asymmetric Ring Opening of Epoxides
Liang, Jian,Soucie, Luke N.,Blechschmidt, Daniel R.,Yoder, Aaron,Gustafson, Addie,Liu, Yu
supporting information, p. 513 - 518 (2019/01/14)
Aromatic donor-acceptor interaction as the driving force to assemble cooperative catalysts is described. Pyrene/naphthalenediimide functionalized Co(III)-salen complexes self-assembled into bimetallic catalysts through aromatic donor-acceptor interactions and showed high catalytic activity and selectivity in the asymmetric ring opening of various epoxides. Control experiments, nuclear magnetic resonance (NMR) spectroscopy titrations, mass spectrometry measurement, and X-ray crystal structure analysis confirmed that the catalysts assembled based on the aromatic donor-acceptor interaction, which can be a valuable noncovalent interaction in supramolecular catalyst development.
Exploring the Biocatalytic Scope of a Novel Enantioselective Halohydrin Dehalogenase from an Alphaproteobacterium
Xue, Feng,Ya, Xiangju,Xiu, Yuansong,Tong, Qi,Wang, Yuqi,Zhu, Xinhai,Huang, He
, p. 629 - 637 (2019/01/25)
A gene encoding halohydrin dehalogenase from an alphaproteobacterium (AbHHDH) was identified, cloned and over-expressed in Escherichia coli. AbHHDH was able to catalyze the stereoselective dehalogenation of prochiral and racemic halohydrins. It showed the highest enantioselectivity in the dehalogenation of 20?mM (R,S)-2-bromo-1-phenylethanol, which yielded (S)-2-bromo-1-phenylethanol with 99% ee and 34.5% yield. Moreover, AbHHDH catalyzed the azidolysis of epoxides with low to moderate (S)-enantioselectivity. The highest enantioselectivity (E = 18.6) was observed when (R,S)-benzyl glycidyl ether was used as the substrate. A sequential kinetic resolution catalyzed by HHDH was employed for the synthesis of chiral 1-chloro-3-phenoxy-2-propanol. We prepared enantiopure (S)-isomer with a high enantiopurity of ee > 99% and a yield of 30.7% (E-value: 21.3) by kinetic resolution of 20?mM substrate. The (S)-isomer with 99% ee readily obtained from 40 to 150?mM (R,S)-1-chloro-3-phenoxy-2-propanol. Taken together, the results of this study demonstrate the applicability of this HHDH for the production of optically active compounds. [Figure not available: see fulltext.].
Imido-P(v) trianion supported enantiopure neutral tetrahedral Pd(II) cages
Rajasekar, Prabhakaran,Pandey, Swechchha,Paithankar, Harshad,Chugh, Jeetender,Steiner, Alexander,Boomishankar, Ramamoorthy
supporting information, p. 1873 - 1876 (2018/02/23)
Charge-neutral chiral hosts are attractive due to their ability to recognize a wide range of guest functionalities and support enantioselective processes. However, reports on such charge-neutral cages are very scarce in the literature. Here, we report an enantiomeric pair of tetrahedral Pd(ii) cages built from chiral tris(imido)phosphate trianions and oxalate linkers, which exhibit enantioselective separation capabilities for epichlorohydrin, β-butyrolactone, and 3-methyl- and 3-ethyl cyclopentanone.
Homochiral Metal-Organic Cage for Gas Chromatographic Separations
Xie, Sheng-Ming,Fu, Nan,Li, Li,Yuan, Bao-Yan,Zhang, Jun-Hui,Li, Yan-Xia,Yuan, Li-Ming
, p. 9182 - 9188 (2018/07/21)
Metal-organic cages (MOCs) as a new type of porous material with well-defined cavities were extensively pursued because of their relative ease of synthesis and their potential applications in host-guest chemistry, molecular recognition, separation, catalysis, gas storage, and drug delivery. Here, we first reported that a homochiral MOC [Zn3L2] is explored to fabricate [Zn3L2] coated capillary column for high-resolution gas chromatographic separation of a wide range of analytes, including n-alkanes, polycyclic aromatic hydrocarbons, and positional isomers, especially for racemates. Various kinds of racemates such as alcohols, diols, epoxides, ethers, halohydrocarbons, and esters were separated with good enantioselectivity and reproducibility on the [Zn3L2] coated capillary column. The fabricated [Zn3L2] coated capillary column exhibited significant chiral recognition complementary to that of a commercial β-DEX 120 column and our recently reported homochiral porous organic cage CC3-R coated column. The results show that the homochiral MOCs will be very attractive as a new type of chiral selector in separation science.
Asymmetric Hydrolytic and Aminolytic Kinetic Resolution of Racemic Epoxides using Recyclable Macrocyclic Chiral Cobalt(III) Salen Complexes
Tak, Rajkumar,Kumar, Manish,Menapara, Tusharkumar,Gupta, Naveen,Kureshy, Rukhsana I.,Khan, Noor-ul H.,Suresh
supporting information, p. 3990 - 4001 (2017/11/22)
New chiral macrocyclic cobalt(III) salen complexes were synthesized and used as catalyst for the asymmetric kinetic resolution (AKR) of terminal epoxides and glycidyl ethers with aromatic/aliphatic amines and water as nucleophiles. This is the first occasion where a Co(III) salen complex demonstrated its ability to catalyze AKR as well as hydrolytic kinetic resolution (HKR) reactions. Excellent enantiomeric excesses of the epoxides, the corresponding amino alcohols and diols (upto 99%) with quantitative yields were achieved by using the chiral Co(III) salen complexes in dichloromethane at room temperature. This protocol was further extended for the synthesis of two important drug molecules, i.e., (S)-propranolol and (R)-naftopidil. The catalytic system was also explored for the synthesis of chirally pure diols and chiral cyclic carbonates using carbon dioxide as a greener renewable C1 source. The catalyst was recycled for upto 5 catalytic cycles with retention of enantioselectivity. (Figure presented.).
Engineering the epoxide hydrolase from Agromyces mediolanus for enhanced enantioselectivity and activity in the kinetic resolution of racemic epichlorohydrin
Xue, Feng,Liu, Zhi-Qiang,Wan, Nan-Wei,Zhu, Hang-Qin,Zheng, Yu-Guo
, p. 31525 - 31532 (2015/04/22)
The biocatalytic production of enantiopure epichlorohydrin (ECH) has been steadily attracting more attention. For industrial applications, it is important to obtain an epoxide hydrolase (EH) that possesses the desired enantioselectivity. Site-saturation and site-directed mutagenesis of the Ser207, Asn240 and Trp182 positions were used to generate variants of EH from Agromyces mediolanus ZJB120203 with enhanced enantioselectivity for the kinetic resolution of racemic ECH. The best variant, VDF (W182F/S207V/N240D), displayed a 7-fold enhanced enantioselectivity toward racemic ECH, with an increase in the enantiomeric ratio value (E value) preferring the (R)-ECH enantiomer from 12.9 of wild-type to 90.0, as well as a 1.7-fold improvement in activity. Furthermore, we successfully applied the created recombinant Escherichia coli whole cells expressing variant VDF in the kinetic resolution of racemic ECH. Enantiopure (S)-ECH could be obtained with an enantiopurity of >99% ee and a yield of 40.5% from 450 mM racemic ECH, which is better than those of other reported EHs. These results demonstrated that the EH obtained in this study could be applied for the efficient resolution of racemic ECH.
Efficient synthesis of (S)-epichlorohydrin in high yield by cascade biocatalysis with halohydrin dehalogenase and epoxide hydrolase mutants
Xue, Feng,Liu, Zhi-Qiang,Wang, Ya-Jun,Zhu, Hang-Qin,Wan, Nan-Wei,Zheng, Yu-Guo
, p. 147 - 149 (2015/10/19)
Enantioselective biotransformation of prochiral 1,3-DCP by halohydrin dehalogenases (HHDHs) is particularly attractive since 100% yield of chiral epichlorohydrin (ECH) may be obtained. HheC mutant (P175S/W249P) displayed greatly improved enantiomeric excess (ee) of (S)-ECH from 5% to 95.3% in the catalyzed dehalogenation of 1,3-DCP at pH 8.0. (S)-ECH was enantioselectively biotransformed from 40 mM 1,3-DCP with 92.3% ee and 93.2% yield at pH 10.0. To increase the ee of (S)-ECH, the catalysis was carried out using HheC mutant coupled with epoxide hydrolase mutant and the maximum yield and ee of (S)-ECH reached 91.2% and > 99%.
