17131-14-5Relevant academic research and scientific papers
Obtaining optical purity for product diols in enzyme-catalyzed epoxide hydrolysis: Contributions from changes in both enantio- and regioselectivity
Carlsson, Asa Janfalk,Bauer, Paul,Ma, Huan,Widersten, Mikael
, p. 7627 - 7637,11 (2012)
Enzyme variants of the plant epoxide hydrolase StEH1 displaying improved stereoselectivities in the catalyzed hydrolysis of (2,3-epoxypropyl)benzene were generated by directed evolution. The evolution was driven by iterative saturation mutagenesis in comb
Substrate scope and selectivity in offspring to an enzyme subjected to directed evolution
Blikstad, Cecilia,Dahlstroem, Kaethe M.,Salminen, Tiina A.,Widersten, Mikael
, p. 2387 - 2398 (2014)
We have analyzed the effects of mutations inserted during directed evolution of a specialized enzyme, Escherichia coli S-1,2-propanediol oxidoreductase (FucO). The kinetic properties of evolved variants have been determined and the observed differences have been rationalized by modeling the tertiary structures of isolated variants and the wild-type enzyme. The native substrate, S-1,2-propanediol, as well as phenylacetaldehyde and 2S-3-phenylpropane-1,2-diol, which are new substrates accepted by isolated variants, were docked into the active sites. The study provides a comprehensive picture of how acquired catalytic properties have arisen via an intermediate generalist enzyme, which had acquired a single mutation (L259V) in the active site. Further mutagenesis of this generalist resulted in a new specialist catalyst. We have also been able to relate the native enzyme activities to the evolved ones and linked the differences to individual amino acid residues important for activity and selectivity. F254 plays a dual role in the enzyme function. First, mutation of F254 into an isoleucine weakens the interactions with the coenzyme thereby increasing its dissociation rate from the active site and resulting in a four-fold increase in turnover number with S-1,2-propanediol. Second, F254 is directly involved in binding of aryl-substituted substrates via π-π interactions. On the other hand, N151 is critical in determining the substrate scope since the side chain amide group stabilizes binding of 1,2-substituted diols and is apparently necessary for enzymatic activity with these substrates. Moreover, the side chain of N151 introduces steric hindrance, which prevents high activity with phenylacetaldehyde. Additionally, the hydroxyl group of T149 is required to maintain the catalytically important hydrogen bonding network. A specialist enzyme, Escherichia coli propanediol oxidoreductase, was subjected to laboratory evolution with the purpose of broadening the substrate scope to include aryl-substituted alcohols and aldehydes. The wild-type enzyme displays very low and undetectable activity with phenylacetaldehyde and 3-phenyl-1,2-propanediol, respectively. Two rounds of directed evolution produced a variant enzyme displaying characteristics of a new specialist and others with traits of generalist enzymes.
Investigation of the role of the 2′,3′-epoxidation pathway in the bioactivation and genotoxicity of dietary allylbenzene analogs
Guenthner,Luo
, p. 47 - 58 (2001)
The genotoxic potential of naturally occurring allylbenzene analogs, including safrole, eugenol, estragole, and others, has been examined in many studies over the past 30 years. It has been established that these compounds are subject to biotransformation in the liver, which can lead to the formation of reactive electrophilic intermediates. The major route of bioactivation is via hydroxylation of the 1′ carbon atom of the allylic side chain. We have synthesized 2′,3′- (allylic) epoxide derivatives of allylbenzene, estragole eugenol and safrole, and have used them to characterize the genotoxic potential of epoxidation at the allylic double bond for allylbenzene and its naturally occurring analogs. In order to assert that this pathway has the potential for genotoxicity, it is necessary to demonstrate (1) that epoxide metabolites of these compounds are capable of forming covalent adducts with DNA bases; and (2) that these epoxide metabolites are actually formed in vivo. We have demonstrated that allylic epoxides derived from allylbenzene and estragole are capable of forming covalent adducts with all four deoxyribonucleotides in vitro and, in the case of deoxyguanosine, form at least four different adducts. We also deduce, from evidence obtained using the isolated perfused rat liver, that formation of potentially genotoxic 2′,3′ epoxide metabolites occurs readily in vivo, but that these metabolites are rapidly further metabolized to less toxic dihydrodiol or glutathione conjugates. We conclude that 2′,3′ epoxide metabolites of allylbenzene analogs are formed in vivo and that these epoxides are sufficiently reactive to facilely form covalent bonds with DNA bases. Epoxide formation at the allylic double bond represents, therefore, a potentially genotoxic bioactivation pathway for allylbenzene analogs. However, comparison of the relative kinetics of epoxide metabolism and epoxide formation suggests that a wide margin of protection from DNA covalent adduct formation exists in the rat liver, thus preventing genotoxicity resulting from this pathway to any significant degree. In this regard, we have also observed that the general rate of epoxide hydrolysis is much greater in human liver than in rat liver. We therefore suggest that while the epoxidation pathway poses a potential genotoxic threat to humans, no actual genotoxicity occurs as a result of this metabolic pathway.
Modification of substrate specificity resulting in an epoxide hydrolase with shifted enantiopreference for (2,3-Epoxypropyl)benzene
Gurell, Ann,Widersten, Mikael
, p. 1422 - 1429 (2010)
Random mutagenesis targeted at hotspots of noncatalytic active-site residues of potato epoxide hydrolase StEH1 combined with an enzyme-activity screen allowed the isolation of enzyme variants displaying altered enantiopreference in the catalyzed hydrolysi
Cobalt-Catalyzed One-Pot Asymmetric Difunctionalization of Alkynes to Access Chiral gem-(Borylsilyl)alkanes
You, Yang'en,Ge, Shaozhong
, p. 20684 - 20688 (2021)
Enantioselective cobalt-catalyzed one-pot hydrosilylation and hydroboration of terminal alkynes has been developed employing a cobalt catalyst generated from Co(acac)2 and (R,R)-Me-Ferrocelane. A variety of terminal alkynes undergo this asymmetric transformation, affording the corresponding gem-(borylsilyl)alkane products with high enantioselectivity (up to 98 % ee). This one-pot reaction combines (E)-selective hydrosilylation of alkynes and consecutive enantioselective hydroboration of (E)-vinylsilanes with one chiral cobalt catalyst. This protocol represents the most straightforward approach to access versatile chiral gem-(borylsilyl)alkanes from readily available alkynes with commercially available cobalt salt and chiral ligand.
The direct amino acid-catalyzed asymmetric incorporation of molecular oxygen to organic compounds
Cordova, Armando,Sunden, Henrik,Engqvist, Magnus,Ibrahem, Ismail,Casas, Jesus
, p. 8914 - 8915 (2004)
We have disclosed the direct catalytic incorporation of 1O2 to aldehydes. The unprecedented amino acid-catalyzed asymmetric α-oxidation of aldehydes with molecular oxygen or air proceeded with high chemoselectivity and was a direct entry for the synthesis of both enantiomers of terminal diols. The results demonstrated that simple amino acids accomplished catalytic asymmetric oxidations with molecular oxygen or air, which has previously been considered to be in the domain of enzymes and chiral transition-metal complexes. The efficiency of the catalytic process may warrant the existence of an ancient pathway for the synthesis of hydroxylated organic compounds. Copyright
The Os/Cu-Al-hydrotalcite catalysed hydroxylation of alkenes
Friedrich, Holger B.,Govender, Mayashree,Makhoba, Xolani,Ngcobo, T. Dennis,Onani, Martin O.
, p. 2922 - 2923 (2003)
A new Os/Cu-Al-hydrotalcite-like catalyst is described which, with N-methylmorpholine oxide as co-oxidant, heterogeneously catalyses the hydroxylation of olefins to give diols selectively and in high yield.
Catalytic oxygen atom transfer promoted by tethered Mo(VI) dioxido complexes onto silica-coated magnetic nanoparticles
Colaiezzi, Roberta,Crucianelli, Marcello,Di Giuseppe, Andrea,Ferella, Francesco,Lazzarini, Andrea,Paolucci, Valentina
, (2021/11/30)
The preparation of three novel active and stable magnetic nanocatalysts for the selective liquid-phase oxidation of several olefins, has been reported. The heterogeneous systems are based on the coordination of cis-MoO2 moiety onto three different SCMNP@Si-(L1-L3) magnetically active supports, functionalized with silylated acylpyrazolonate ligands L1, L2 and L3. Nanocatalysts thoroughly characterized by ATR-IR spectroscopy, TGA and ICP-MS analyses, showed excellent catalytic performances in the oxidation of conjugated or unconjugated olefins either in organic or in aqueous solvents. The good magnetic properties of these catalytic systems allow their easy recyclability, from the reaction mixture, and reuse over five runs without significant decrease in the activity, either in organic or water solvent, demonstrating their versatility and robustness.
Diastereoselective Alkene Hydroesterification Enabling the Synthesis of Chiral Fused Bicyclic Lactones
Shi, Zhanglin,Shen, Chaoren,Dong, Kaiwu
supporting information, p. 18039 - 18042 (2021/11/16)
Palladium-catalysed diastereoselective hydroesterification of alkenes assisted by the coordinative hydroxyl group in the substrate afforded a variety of chiral γ-butyrolactones bearing two stereocenters. Employing the carbonylation-lactonization products as the key intermediates, the route from the alkenes with single chiral center to chiral THF-fused bicyclic γ-lactones containing three stereocenters was developed.
Lewis Base Catalyzed Dioxygenation of Olefins with Hypervalent Iodine Reagents
Pan, Liangkun,Ke, Zhihai,Yeung, Ying-Yeung
supporting information, p. 8174 - 8178 (2021/10/25)
1,2-Diols are extremely useful building blocks in organic synthesis. Hypervalent iodine reagents are useful for the vicinal dihydroxylation of olefins to give 1,2-diols under metal-free conditions, but strongly acidic promoters are often required. Herein, we report a catalytic vicinal dioxygenation of olefins with hypervalent iodine reagents using Lewis bases as catalysts. The conditions are mild and compatible with various functional groups.
