533-60-8Relevant articles and documents
Selective oxidation of 1,2-diols by electrochemical method using organotin compound and bromide ion as mediators
Maki, Toshihide,Fukae, Kazuhiro,Harasawa, Hitomi,Ohishi, Takahiro,Matsumura, Yoshihiro,Onomura, Osamu
, p. 651 - 654 (1998)
A new electrochemical method for a selective oxidation of 1,2-diols to keto alcohols was explored. The method used dibutyltin oxide and bromide ion as mediators, and the oxidation was found to proceed effectively at 0°C under neutral conditions. Under these reaction conditions, 1,2-cyclohexanediol was selectively oxidized even in the presence of primary and secondary alcohols.
A zinc-dependent alcohol dehydrogenase (ADH) from Thauera aromatica, reducing cyclic α- And β-diketones
Loderer, Christoph,Morgenstern, Frances,Ansorge-Schumacher, Marion
, p. 1872 - 1880 (2015)
Zinc-dependent alcohol dehydrogenases (ADHs) are valuable biocatalysts for the synthesis of chiral hydroxy compounds such as α-hydroxy ketones and diols, both valuable precursors for the synthesis of various pharmaceuticals. However, while highly active on aliphatic or phenyl-substituted diketones, most well characterized ADHs show no significant activity on cyclic α- and β-diketones. Therefore, this study aimed at the detection of a novel ADH capable to reduce these special targets. It involved a rational screening of biochemical pathways for enzymes with structurally related natural substrates. The so detected 6-hydroxycyclohex-1-ene-1-carbonyl-CoA dehydrogenase (ThaADH) from Thauera aromatica was cloned, expressed in Escherichia coli and purified by affinity chromatography. The characterization revealed a substrate specificity with highest activities on cyclic α- and β-diketones including 1,2-cyclohexanedione and 1,3-cyclopentanedione. Structural reasons for this extraordinary substrate spectrum were investigated with a homology model created via Swiss Model server. Although the quality of the model may be improved, it suggests that a bulky aromatic residue, that plays a crucial role in the definition of the substrate binding pockets of most ADHs, is replaced by a glycine residue in ThaADH. We propose that this structural difference leads to the formation of one large binding pocket instead of two smaller ones and consequently to a preference for cyclic diketones over linear bulky substrates. Thus, we have achieved both provision of a novel biocatalyst with high potential in chiral synthesis, and a possible explanation for the measured differences to known ADHs. The described structural motif might be used for identification of further enzymes with a related substrate scope.
Citric acid mediated catalytic osmylation/oxidative cleavage of electron deficient olefins: A vinyl sulfone study
Bobinski, Thomas P.,Fuchs, Philip L.
, p. 4151 - 4154 (2015)
The first broad catalytic dihydroxylation of enantiopure cyclic vinyl sulfones followed by oxidative cleavage of the resulting acyloin provides linear termini-differentiated polyketide fragments. This mild vinyl sulfone cleavage provides an effective alternative to the current ozonolysis protocol.
Aerobic photooxidation in water by polyoxotungstates: The case of uracil
Bonchio, Marcella,Carraro, Mauro,Conte, Valeria,Scorrano, Gianfranco
, p. 4897 - 4903 (2005)
Uracil photooxygenation occurs in acidic water (pH = 1) at 25°C, under oxygen (1 atm), irradiating with γ > 300 nm in the presence of selected polyoxometalates (POM). A marked diversity of photocatalytic behavior is registered for different POMs in terms of oxidation rate and selectivity. H 3PW12O40 (PW12) appears to be the most reactive photocatalyst, by far superior to isostructural complexes, leading to a product distribution typical of OH. dominated oxidations, while Na4W10O32 (W10) and Na 12[WZn3(H2O)2(ZnW9O 34)2] (Zn5W19) exhibit a preferential reactivity towards uracil glycol. Kinetic studies and radical scavenger probes, performed on target intermediates and model diols, highlight a substantial difference in the mechanism of photocatalysis by the three complexes. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
Selective Isomerization via Transient Thermodynamic Control: Dynamic Epimerization of trans to cis Diols
Macmillan, David W. C.,Oswood, Christian J.
supporting information, p. 93 - 98 (2022/01/03)
Traditional approaches to stereoselective synthesis require high levels of enantio- and diastereocontrol in every step that forms a new stereocenter. Here, we report an alternative approach, in which the stereochemistry of organic substrates is selectivel
Activation of H2O2over Zr(IV). Insights from Model Studies on Zr-Monosubstituted Lindqvist Tungstates
Abramov, Pavel A.,Carbó, Jorge J.,Chesalov, Yuriy A.,Eltsov, Ilia V.,Errington, R. John,Evtushok, Vasilii Yu.,Glazneva, Tatyana S.,Ivanchikova, Irina D.,Kholdeeva, Oxana A.,Maksimchuk, Nataliya V.,Maksimov, Gennadii M.,Poblet, Josep M.,Solé-Daura, Albert,Yanshole, Vadim V.,Zalomaeva, Olga V.
, p. 10589 - 10603 (2021/09/02)
Zr-monosubstituted Lindqvist-type polyoxometalates (Zr-POMs), (Bu4N)2[W5O18Zr(H2O)3] (1) and (Bu4N)6[{W5O18Zr(μ-OH)}2] (2), have been employed as molecular models to unravel the mechanism of hydrogen peroxide activation over Zr(IV) sites. Compounds 1 and 2 are hydrolytically stable and catalyze the epoxidation of C?C bonds in unfunctionalized alkenes and α,β-unsaturated ketones, as well as sulfoxidation of thioethers. Monomer 1 is more active than dimer 2. Acid additives greatly accelerate the oxygenation reactions and increase oxidant utilization efficiency up to >99%. Product distributions are indicative of a heterolytic oxygen transfer mechanism that involves electrophilic oxidizing species formed upon the interaction of Zr-POM and H2O2. The interaction of 1 and 2 with H2O2 and the resulting peroxo derivatives have been investigated by UV-vis, FTIR, Raman spectroscopy, HR-ESI-MS, and combined HPLC-ICP-atomic emission spectroscopy techniques. The interaction between an 17O-enriched dimer, (Bu4N)6[{W5O18Zr(μ-OCH3)}2] (2′), and H2O2 was also analyzed by 17O NMR spectroscopy. Combining these experimental studies with DFT calculations suggested the existence of dimeric peroxo species [(μ-?2:?2-O2){ZrW5O18}2]6- as well as monomeric Zr-hydroperoxo [W5O18Zr(?2-OOH)]3- and Zr-peroxo [HW5O18Zr(?2-O2)]3- species. Reactivity studies revealed that the dimeric peroxo is inert toward alkenes but is able to transfer oxygen atoms to thioethers, while the monomeric peroxo intermediate is capable of epoxidizing C?C bonds. DFT analysis of the reaction mechanism identifies the monomeric Zr-hydroperoxo intermediate as the real epoxidizing species and the corresponding α-oxygen transfer to the substrate as the rate-determining step. The calculations also showed that protonation of Zr-POM significantly reduces the free-energy barrier of the key oxygen-transfer step because of the greater electrophilicity of the catalyst and that dimeric species hampers the approach of alkene substrates due to steric repulsions reducing its reactivity. The improved performance of the Zr(IV) catalyst relative to Ti(IV) and Nb(V) catalysts is respectively due to a flexible coordination environment and a low tendency to form energy deep-well and low-reactive Zr-peroxo intermediates.
