23357-51-9Relevant academic research and scientific papers
One-pot kinetic resolution-Mitsunobu reaction to access optically pure compounds, using silver salts in the substitution protocol
Raval, Hiten B.,Bedekar, Ashutosh V.
, p. 21238 - 21243 (2020/12/31)
A practical method is developed to access chiral arylalkyl carbinols with a high yield from racemic alcohols. A one-pot enzyme mediated Kinetic Resolution followed by Mitsunobu esterification of the unreacted enantiomer of alcohol with metal acetate results in a nearly complete formation of chiral acetate. Substitution with AgOAc was found to be the most efficient, and the use of sub stoichiometric amounts of AgNO3 and excess of NaOAc affords comparable results; the protocol was further extended to introduce azide as a nucleophile.
Identification of an Esterase Isolated Using Metagenomic Technology which Displays an Unusual Substrate Scope and its Characterisation as an Enantioselective Biocatalyst
Gavin, Declan P.,Murphy, Edel J.,Foley, Aoife M.,Castilla, Ignacio Abreu,Reen, F. Jerry,Woods, David F.,Collins, Stuart G.,O'Gara, Fergal,Maguire, Anita R.
, p. 2466 - 2474 (2019/03/11)
Evaluation of an esterase annotated as 26D isolated from a marine metagenomic library is described. Esterase 26D was found to have a unique substrate scope, including synthetic transformations which could not be readily effected in a synthetically useful manner using commercially available enzymes. Esterase 26D was more selective towards substrates which had larger, more sterically demanding substituents (i. e. iso-propyl or tert-butyl groups) on the β-carbon, which is in contrast to previously tested commercially available enzymes which displayed a preference for substrates with sterically less demanding substituents (e.g. methyl group) at the β-carbon. (Figure presented.).
CO2-expanded bio-based liquids as novel solvents for enantioselective biocatalysis
Hoang, Hai Nam,Nagashima, Yoshihiro,Mori, Shuichi,Kagechika, Hiroyuki,Matsuda, Tomoko
, p. 2984 - 2989 (2017/04/26)
For the first time, CO2-expanded bio-based liquids were reported as novel and sustainable solvents for biocatalysis. Herein, it was found that by expansion with CO2, 2-methyltetrahydrofuran (MeTHF), and other bio-based liquids, which were not favorable solvents for immobilized Candida antarctica lipase B (Novozym 435) catalyzed transesterification, were tuned into excellent reaction media. Especially, for the kinetic resolution of challenging bulky secondary substrates such as rac-1-adamantylethanol, the lipase displayed very high activity with excellent enantioselectivity (E value > 200) in CO2-expanded MeTHF (MeTHF concentration 10% v/v, 6 MPa), whereas there was almost no activity observed in conventional organic solvents.
Ligand effect in racemization and dynamic kinetic resolution of alcohols: Mechanism on cymene ruthenium complexes
Cao, Hui,Cai, Li-Hua,Wang, Chen-Xi,Zhu, Xiao-Han,Li, Zhi-Ming,Hou, Xiu-Feng
, p. 60 - 66 (2014/12/11)
A family of ruthenium complexes with different ligands was utilized in racemization of (R)-1-phenylethanol to investigate the potential influence of the ligands coordinated to the ruthenium center. Kinetic experiments showed that 16-electron cymene ruthenium complex with two chloro-bridge bonds and 18-electron ones with easily dissociative ligands are highly active for catalytic racemization of alcohols. Possible racemization mechanism for cymene ruthenium complexes was then proposed. Computational analysis of dissociation energy barrier, NBO analysis and reaction potential energy surface suggest that ligand-dissociation process is the vital step of the racemization catalyzed by cymene ruthenium complexes. Thereafter, these complexes were applied in the DKR of secondary alcohols to verify their efficiency and applicability.
Kinetic resolution of secondary alcohols with Burkholderia cepacia lipase immobilized on a biodegradable ternary blend polymer matrix as a highly efficient and heterogeneous recyclable biocatalyst
More, Ganesh V.,Badgujar, Kirtikumar C.,Bhanage, Bhalchandra M.
, p. 4592 - 4598 (2015/02/19)
The present work reports a highly efficient and biocatalytic heterogeneous protocol for kinetic resolution (KR) of racemic secondary alcohols with vinyl acetate as an acyl donor, using the biocatalyst Burkholderia cepacia lipase (BCL) immobilized on a biodegradable ternary blend support through polylactic acid (PLA)/polyvinyl alcohol (PVA)/chitosan (CHI); (PLA/PVA/CHI-BCL). The KR reaction with various substituted aromatic, heterocyclic racemic secondary alcohols gave enantiomerically pure alcohol and its enantioenriched acetate derivatives with high conversion (45-50%) and excellent enantiomeric excess (up to 99% ee) at optimized reaction conditions. The reaction works under mild conditions using simple and inexpensive starting materials such as racemic alcohols, vinyl acetate, and immobilized biocatalyst. The given protocol provides excellent recyclability with good yield and enantiomeric excess values up to the studied range of five cycles. The resultant products were characterized with the help of different analytical techniques such as 1H and 13C-NMR, chiral HPLC column, polarimeter, IR and GC-MS.
Efficient benzylic and aliphatic C-H oxidation with selectivity for methylenic sites catalyzed by a bioinspired manganese complex
Shen, Duyi,Miao, Chengxia,Wang, Shoufeng,Xia, Chungu,Sun, Wei
supporting information, p. 1108 - 1111 (2014/03/21)
A benzimidazole-based nonheme manganese complex efficiently catalyzes benzylic, aliphatic C-H as well as tertiary C-H oxidation with hydrogen peroxide as the oxidant in the presence of acetic acid as additive. 18O labeling experiments suggest the reaction may proceed via a high-valent manganese-oxo intermediate.
Separation of enantiopure m-substituted 1-phenylethanols in high space-time yield using Bacillus subtilis esterase
Zheng, Gao-Wei,Liu, Xu-Yun,Zhang, Zhi-Jun,Tian, Ping,Lin, Guo-Qiang,Xu, Jian-He
, p. 20446 - 20449 (2013/11/06)
A recombinant Bacillus subtilis esterase (BsE) expressed in E. coli was found to exhibit excellent enantioselectivity (E was always greater than 100) towards m-substituted 1-phenylethanol acetates in the enantioselective hydrolysis reaction. An explanation for the high enantioselectivity observed towards these substrates was provided by molecular modeling. Moreover, the BsE also showed strong tolerance towards a high concentration of m-substituted 1-phenylethanol acetates (up to 1 M). Based on these excellent catalytic properties of BsE, a kind of m-substituted 1-phenylethanols, (R)-1-(3-chlorophenyl)ethanol, was efficiently synthesized in space-time yield of 920 g per L per day and 97% ee, indicating that the BsE was considered as a potentially ideal and promising biocatalyst for large-scale production of optically active m-substituted 1-phenylethanols. The Royal Society of Chemistry 2013.
Evaluation of snake venom phospholipase A2: Hydrolysis of non-natural esters
Pirolla, Renan A. S.,Baldasso, Paulo A.,Marangoni, Se?rgio,Moran, Paulo J. S.,Rodrigues, Jose? Augusto R.
experimental part, p. 300 - 307 (2011/10/05)
Phospholipase A2 from the rattlesnake Crotalus durissus terrificus was employed for the first time to test its enantioseletivity on the hydrolysis of different non-natural esters. It was observed that the structure of this small enzyme is restrictive in the choice of its lipase action with non-natural substrates. Two forms of the enzyme were used; free and as its cross-linked enzyme aggregate (CLEA). With all substrates, the free enzyme showed activity similar to the CLEA preparation. The advantage of the CLEA phospholipase is the possibility to reuse it in several consecutive reactions without a decrease of activity and selectivity with good but higher yields and ee than with the free enzyme.
Racemization of secondary alcohols catalyzed by ruthenium: Application to chemoenzymatic dynamic resolution
Merabet-Khelassi, Mounia,Vriamont, Nicolas,Aribi-Zouioueche, Louisa,Riant, Olivier
experimental part, p. 1790 - 1796 (2012/01/03)
In this paper, we have shown that the [RuCl2(p-cymene)] 2 complex associated with simple hemisalen ligands is able to racemize (S)-1-phenylethanol. The influence on the racemization process of the ligand's structure as well as the nature of a co-catalyst have been evaluated and optimized. This [RuCl2(p-cymene)]2/Ligand/TEMPO racemization system was then associated with the Candida Antarctica B lipase in order to carry out dynamic kinetic resolution experiments on rac-phenylethanol. This led us to identify the best conditions for effective DKR, which was then applied to various secondary benzylic and aliphatic alcohols. It was thus possible to obtain (R)-1-cyclohexylethyl acetate from rac-1-cyclohexylethanol in quantitative conversion and with high enantioselectivity (98%).
Enzymatic resolution of α-tetralols by CALB-catalyzed acetylation
Ferraz, Helena M.C.,Bianco, Graziela G.,Teixeira, Carla C.,Andrade, Leandro H.,Porto, Andre L.M.
, p. 1070 - 1076 (2008/02/08)
A series of homochiral α-tetralols, as well as their respective acetates, has been obtained by esterification of racemic tetralols, using Candida antarctica lipase (CALB-Novozym 435) as the biocatalyst. This enzyme is shown to be highly efficie
