- COMPOSITES, METHODS AND USES THEREOF
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The present invention relates, in general terms, to methods of catalysing a reaction, including the steps of contacting a chemical entity comprising a sulphide moiety with a composite and an oxidant. The composite acts as a heterogeneous catalyst to oxidise the sulphide moiety. The present invention also relates to composites, methods of synthesising the composites and its use as a catalyst thereof.
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Page/Page column 28
(2021/06/04)
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- Cobalt Single-Atom-Intercalated Molybdenum Disulfide for Sulfide Oxidation with Exceptional Chemoselectivity
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The identification of chemoselective oxidation process en route to fine chemicals and specialty chemicals is a long-standing pursuit in chemical synthesis. A vertically structured, cobalt single atom-intercalated molybdenum disulfide catalyst (Co1-in-MoS2) is developed for the chemoselective transformation of sulfides to sulfone derivatives. The single-atom encapsulation alters the electron structure of catalyst owing to confinement effect and strong metal–substrate interaction, thus enhancing adsorption of sulfides and chemoselective oxidation at the edge sites of MoS2 to achieve excellent yields of up to 99% for 34 examples. The synthetic scopes can be extended to sulfide-bearing alkenes, alkynes, aldehydes, ketones, boronic esters, and amines derivatives as a toolbox for the synthesis of high-value, multifunctional sulfones and late-stage functionalization of pharmaceuticals, e.g., Tamiflu. The synthetic utility of cobalt single atom-intercalated MoS2, together with its reusability, scalability, and simplified purification process, renders it promising for industrial productions.
- Chen, Zhongxin,Liu, Cuibo,Liu, Jia,Li, Jing,Xi, Shibo,Chi, Xiao,Xu, Haisen,Park, In-Hyeok,Peng, Xinwen,Li, Xing,Yu, Wei,Liu, Xiaowang,Zhong, Linxin,Leng, Kai,Huang, Wei,Koh, Ming Joo,Loh, Kian Ping
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- Metal- and additive-free oxygen-atom transfer reaction: an efficient and chemoselective oxidation of sulfides to sulfoxides with cyclic diacyl peroxides
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Metal- and additive-free oxidation of a series of sulfides/thioketones has been achieved using cyclic diacyl peroxides as mild oxygen sources. This protocol features simple manipulation, high chemo- and diastereoselectivity, and a broad substrate scope (up to 42 examples), tolerates many common functional groups, and is scalable and applicable to the late-stage sulfoxidation strategy. A preliminary mechanistic study by quantum mechanical calculations suggests that a single two-electron transfer process is energetically more favorable, and indicates the reactivity of cyclic diacyl peroxides distinct from conventional acyclic acyl peroxides.
- Gan, Shaoyan,Yin, Junjie,Yao, Yuan,Liu, Yang,Chang, Denghu,Zhu, Dan,Shi, Lei
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supporting information
p. 2647 - 2654
(2017/04/03)
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- A chemoselective ipso-hydroxylation of arylboronic acids using urea-hydrogen peroxide under catalyst free condition
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An efficient and practical method for the chemoselective ipso-hydroxylation of arylboronic acids is demonstrated using urea-hydrogen peroxide under catalyst free condition at room temperature. Remarkably, oxidation sensitive functional groups such as olefin, aldehyde, alcohol, ketone, and sulfide as well as heterocycles such as pyridine and thiophene were tolerated under the standard reaction condition. In addition to the solution phase, a solid phase ipso-hydroxylation of arylboronic acids has been investigated with urea hydrogen peroxide. The scope and limitations of the solid phase protocol is discussed.
- Gupta, Surabhi,Chaudhary, Priyanka,Srivastava, Vandana,Kandasamy, Jeyakumar
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supporting information
p. 2506 - 2510
(2016/05/24)
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- Selective sulfoxidation of thioethers and thioaryl boranes with nitrate, promoted by a molybdenum-copper catalytic system
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The catalytic reduction of nitrate by molybdo-enzymes plays a central role in the global biological cycle of nitrogen. However, the use of nitrates as oxidants in synthetic organic chemistry is very limited and typically requires very strong acidic and other extreme reaction conditions. We have developed a highly chemoselective and efficient catalytic process for the sulfoxidation of thioethers and arylthioethers containing boronic acid or boronic ester functional groups, using nitrate salts as oxidants. This homogeneous catalytic reaction was carried out in acetonitrile, where the MoO2Cl 2(OPPh3)2 complex 1 or a mixture of complex 1 with Cu(NO3)2 were used as catalysts. We examined the reaction mechanism using 1H, 15N, and 31P NMR techniques and 18O-labeled sodium nitrate (NaN18O 3) and show that the thioethers are oxidized by nitrate, generating nitrite. Our work adds to the existing chemical transformations available for organoboron compounds, providing straightforward accessibility to a variety of new substrates that could be suitable for Suzuki cross-coupling chemistry.
- Marom, Hanit,Antonov, Svetlana,Popowski, Yanay,Gozin, Michael
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experimental part
p. 5240 - 5246
(2011/08/09)
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