934-73-6Relevant articles and documents
Chiral Ligands in Hypervalent Iodine Compounds: Synthesis and Structures of Binaphthyl-Based λ3-Iodanes
Zhang, Huaiyuan,Cormanich, Rodrigo A.,Wirth, Thomas
supporting information, (2021/12/22)
Several novel binaphthyl-based chiral hypervalent iodine(III) reagents have been prepared and structurally analysed. Various asymmetric oxidative reactions were applied to evaluate the reactivities and stereoselectivities of those reagents. Moderate to excellent yields were observed; however, very low stereoselectivities were obtained. NMR experiments indicated that these reagents are very easily hydrolysed in either chloroform or DMSO solvents leading to the limited stereoselectivities. It is concluded that the use of chiral ligands is an unsuccessful way to prepare efficient stereoselective iodine(III) reagents.
Two enantiocomplementary Baeyer-Villiger monooxygenases newly identified for asymmetric oxyfunctionalization of thioether
Liu, Yafei,Ni, Ye,Wei, Shiyu,Xu, Guochao,Zhou, Jieyu
, (2021/08/19)
Two enantiocomplementary Baeyer-Villiger monooxygenases RaBVMO and AmBVMO were identified by genome mining for the asymmetric sulfoxidation. Both recombinant BVMOs have optimal pH of 9.0 and temperature of 35 °C. The half-lives of RaBVMO and AmBVMO at 30 °C were 24.4 and 24.6 h. RaBVMO and AmBVMO exhibited broad substrate spectrum and could catalyze the oxidization of various compounds including fatty ketones, cyclic ketones, and thioethers. Kinetic parameters analysis revealed that both RaBVMO and AmBVMO displayed higher catalytic efficiency toward thioanisole than cyclohexanone. As much as 50 mM thioanisole could be completely oxidized by AmBVMO and RaBVMO with 99% (R) and 95% (S), respectively. Molecular docking analysis further provides evidence for the complementary enantioselectivity of RaBVMO and AmBVMO. Our results demonstrate the potential application of the two novel BVMOs in asymmetric synthesis of sulfoxides.
The Stereoselective Oxidation of para-Substituted Benzenes by a Cytochrome P450 Biocatalyst
Chao, Rebecca R.,Lau, Ian C.-K.,Coleman, Tom,Churchman, Luke R.,Child, Stella A.,Lee, Joel H. Z.,Bruning, John B.,De Voss, James J.,Bell, Stephen G.
, p. 14765 - 14777 (2021/09/14)
The serine 244 to aspartate (S244D) variant of the cytochrome P450 enzyme CYP199A4 was used to expand its substrate range beyond benzoic acids. Substrates, in which the carboxylate group of the benzoic acid moiety is replaced were oxidised with high activity by the S244D mutant (product formation rates >60 nmol.(nmol-CYP)?1.min?1) and with total turnover numbers of up to 20,000. Ethyl α-hydroxylation was more rapid than methyl oxidation, styrene epoxidation and S-oxidation. The S244D mutant catalysed the ethyl hydroxylation, epoxidation and sulfoxidation reactions with an excess of one stereoisomer (in some instances up to >98 %). The crystal structure of 4-methoxybenzoic acid-bound CYP199A4 S244D showed that the active site architecture and the substrate orientation were similar to that of the WT enzyme. Overall, this work demonstrates that CYP199A4 can catalyse the stereoselective hydroxylation, epoxidation or sulfoxidation of substituted benzene substrates under mild conditions resulting in more sustainable transformations using this heme monooxygenase enzyme.
Polyoxometalate-Based Organic-Inorganic Hybrids as Heterogeneous Catalysts for Cycloaddition of CO2with Epoxides and Oxidative Desulfurization Reactions
Zhao, Yu-Qing,Liu, Ying-Ying,Ma, Jian-Fang
, p. 1019 - 1027 (2021/01/13)
Self-assembly of polyoxometalates, transition metal salts, and 2,6-bis(2′-pyridyl)-4-hydroxypyridine (LOH) obtained four organic-inorganic hybrids [Co2.5(LOH)(LO)2(H2O)2(PW12O39)]·3CH3CN·2OH (1), [Zn1.5(LOH)3]·(PMo12O40)·CH3OH·2H2O (2), [Cd1.5(LOH)3]·(PW12O40)·2CH3OH·1.5H2O (3), and [Mn(LOH)2]·(PW12O40)·2CH3CN·H3O (4). Hybrid 1 exhibits an extended chain, which could be further connected into a 3D supramolecular architecture by H-bonds. Hybrids 2-4 feature monomolecular structures, which are further bridged via H-bonds to yield charming 3D supramolecular structures. Noteworthy, 1 and 2 can be employed as recyclable and highly efficient heterogeneous catalysts. The activated 1 displays a high catalytic activity for the cycloaddition reaction of CO2 and epoxides. Hybrid 2 exhibits an excellent catalytic performance for the oxidative desulfurization reaction.
Synthesis of a light-harvesting ruthenium porphyrin complex substituted with BODIPY units. Implications for visible light-promoted catalytic oxidations
Malone, Jonathan,Klaine, Seth,Alcantar, Christian,Bratcher, Fox,Zhang, Rui
, p. 4977 - 4985 (2021/03/26)
A light-harvesting ruthenium porphyrin substituted covalently with four boron-dipyrrin (BODIPY) moieties has been synthesized and studied. The resulting complex showed an efficient decarbonylation reaction predominantly due to a photo-induced energy transfer process. Chemical oxidation of the ruthenium(ii) BODIPY-porphyrin afforded a high-energytrans-dioxoruthenium(vi) species that is one order of magnitude more reactive towards alkene oxidation than those analogues supported by conventional porphyrins. In the presence of visible light, the ruthenium(ii) BODIPY-porphyrin displayed remarkable catalytic activity toward sulfide oxidation and alkene epoxidation using iodobenzene diacetate [PhI(OAc)2] and 2,6-dichloropyridineN-oxide (Cl2pyNO) as terminal oxidants, respectively. The findings in this work highlight that porphyrin-BODIPY conjugated metal complexes are potentially useful for visible light-promoted catalytic oxidations.
Assembly of polyoxometalate-thiacalix[4]arene-based inorganic-organic hybrids as efficient catalytic oxidation desulfurization catalysts
Li, Jie,Du, Peng,Liu, Ying-Ying,Ma, Jian-Fang
supporting information, p. 1349 - 1356 (2021/02/09)
Self-assembly of polyoxometalates, Ni(ii)/Ag(i) cations and tetra-[5-(mercapto)-1-methyltetrazole]-thiacalix[4]arene (L) yielded three inorganic-organic hybrids, namely, [Ni3L2(CH3OH)6(H2O)4][PMo12O40]2·3CH3OH·2H2O (1), [Ni3L2(CH3OH)6(H2O)4][PW12O40]2·3CH3OH·2H2O (2) and [Ag3L(PMo12O40)] (3). In hybrids (1) and (2), Ni(ii) cations are linked by L ligands to produce layered frameworks, and H bonds among the [PMo12O40]3?/[PW12O40]3?anions and L ligands lengthen the structures to form 3D supramolecular architectures. Hybrid (3) exhibits a 3D architecture, of which Ag(i) cations not only coordinated with the N and O atoms of L ligands and [PMo12O40]3?anions simultaneously, but also connected each other by Ag-Ag interactions. It is worth mentioning that1and3as recyclable catalysts show excellent heterogeneous catalytic activity in oxidation desulfurization reactions.
Air atmospheric photocatalytic oxidation by ultrathin C,N-TiO2nanosheets
Cheng, Xiuyan,Zhang, Jianling,Liu, Lifei,Zheng, Lirong,Zhang, Fanyu,Duan, Ran,Sha, Yufei,Su, Zhuizhui,Xie, Fei
supporting information, p. 1165 - 1170 (2021/02/26)
Herein, we demonstrate the highly efficient photocatalytic sulfide oxidation reaction under mild conditions,i.e.in air, at room temperature and in the absence of a sacrificial reagent, co-catalyst or redox mediator, by using ultrathin C,N-TiO2nanosheets as a photocatalyst.
COVALENT ORGANIC FRAMEWORKS AND APPLICATIONS AS PHOTOCATALYSTS
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Paragraph 00146; 00169, (2021/05/21)
Described herein are covalent organic frameworks. The covalent organic frameworks have unique structural and physical properties, which lends them to be versatile in a number of different applications and uses. In one aspect, the covalent organic frameworks are composed of a plurality of fused aromatic groups and electron-deficient chromophores. The covalent organic frameworks are useful as photocatalysts in a number of different applications.
Organocatalytic sulfoxidation
Davidson, Stuart C.,Gomes, Gabriel dos Passos,Kuhn, Leah R.,Alabugin, Igor V.,Kennedy, Alan R.,Tomkinson, Nicholas C.O.
, (2020/12/07)
Treatment of a sulfide with a catalytic amount of a 1,3-diketone in the presence of silica sulfuric acid as a co-catalyst and hydrogen peroxide (50% aq) as the stoichiometric oxidant leads to the corresponding sulfoxide product. The reaction is effective for diaryl, aryl-alkyl and dialkyl sulfides and is tolerant of oxidisable and acid sensitive functional groups. Investigations have shown that the tris-peroxide 2, formed on reaction of pentane-2,4-dione with hydrogen peroxide under acidic reaction conditions, can oxidise two equivalents of sulfide using the exocyclic peroxide groups whereas the endocyclic peroxide remains intact. Calculations provide a mechanism consistent with experimental observations and suggest the reaction proceeds via an initial acid catalysed ring opening of a protonated tris-peroxide prior to oxygen transfer to a sulfur nucleophile.
Integrating hydrogen production with anodic selective oxidation of sulfides over a CoFe layered double hydroxide electrode
Ma, Lina,Zhou, Hua,Xu, Ming,Hao, Peipei,Kong, Xianggui,Duan, Haohong
, p. 938 - 945 (2021/02/06)
Replacing the sluggish oxygen evolution reaction (OER) with oxidation reactions for the synthesis of complex pharmaceutical molecules coupled with enhanced hydrogen evolution reaction (HER) is highly attractive, but it is rarely explored. Here, we report an electrochemical protocol for selective oxidation of sulfides to sulfoxides over a CoFe layered double hydroxide (CoFe-LDH) anode in an aqueous-MeCN electrolyte, coupled with 2-fold promoted cathodic H2productivity. This protocol displays high activity (85-96% yields), catalyst stability (10 cycles), and generality (12 examples) in selective sulfide oxidation. We demonstrate its applicability in the synthesis of four important pharmaceutical related sulfoxide compounds with scalability (up to 1.79 g). X-ray spectroscopy investigations reveal that the CoFe-LDH material evolved into amorphous CoFe-oxyhydroxide under catalytic conditions. This work may pave the way towards sustainable organic synthesis of valuable pharmaceuticals coupled with H2production.
