1792-81-0Relevant articles and documents
A heterogeneous cis-dihydroxylation catalyst with stable, site-isolated osmium-diolate reaction centers
Severeyns, An,De Vos, Dirk E.,Fiermans, Lucien,Verpoort, Francis,Grobet, Piet J.,Jacobs, Pierre A.
, p. 586 - 589 (2001)
Involatile OsO4! A tetrasubstituted olefin is immobilized on SiO2 and reacts with OsO4 to form a stable osmate (IV) ester (see scheme), which is a leak-proof heterogeneous catalyst for the cis-dihydroxylation of olefins.
Ionic liquid-immobilized catalytic system for biomimetic dihydroxylation of olefins
Closson, Adam,Johansson, Mikael,Baeckvall, Jan-E.
, p. 1494 - 1495 (2004)
A biomimetic catalytic system for dihydroxylation of olefins consisting of OsO4, N-methylmorpholine, and a flavin has been immobilized in an ionic liquid. This immobilized catalytic system is highly efficient for dihydroxylation with 30% aqueous H2O2 and it can be reused (at least 5 times) without loss of activity.
Osmium(III) and osmium(V) complexes bearing a macrocyclic ligand: A simple and efficient catalytic system for cis-dihydroxylation of alkenes with hydrogen peroxide
Sugimoto, Hideki,Ashikari, Kenji,Itoh, Shinobu
, p. 2154 - 2160 (2013)
A simple protocol that uses [OsIII(OH)(H2O)(L-N 4Me2)](PF6)2 (1; L-N 4Me2=N,N′-dimethyl-2,11-diaza[3.3](2,6) pyridinophane) as a catalyst and H2O2 as a terminal oxidant for efficient cis-1,2-dihydroxylation of alkenes is presented. Unfunctionalized (or aliphatic) alkenes and alkenes/styrenes containing electron-withdrawing groups are selectively oxidized to the corresponding vicinal diols in good to excellent yields (46-99 %). In the catalytic reactions, the stoichiometry of alkene:H2O2 is 1:1, and thus the oxidant efficiency is very high. For the dihydroxylation of cyclohexene, the catalytic amount of 1 can be reduced to 0.01 mol % to achieve a very high turnover number of 5500. The active oxidant is identified as the Os V(O)(OH) species (2), which is formed via the hydroperoxide adduct, an OsIII(OOH) species. The active oxidant 2 is successfully isolated and crystallographically characterized. The wizard of Os: A simple protocol that uses [OsIII(OH)(H2O)(L-N4Me 2)](PF6)2 (1) and H2O2 for efficient cis-1,2-dihydroxylation of alkenes is presented. Unfunctionalized (or aliphatic) alkenes and alkenes/styrenes containing electron-withdrawing groups were converted into the corresponding vicinal diols in good to excellent yields. It has been confirmed that the OsV(O)(OH) species (2) is the active oxidant, which is formed via the hydroperoxide adduct A. Copyright
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Gunstone,Morris
, p. 487,489 (1957)
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Contribution of flavonoids and catechol to the reduction of ICAM-1 expression in endothelial cells by a standardised Willow bark extract
Freischmidt,Jürgenliemk,Kraus,Okpanyi,Müller,Kelber,Weiser,Heilmann
, p. 245 - 252 (2012)
Introduction: A quantified aqueous Willow bark extract (STW 33-I) was tested concerning its inhibitory activity on TNF-α induced ICAM-1 expression in human microvascular endothelial cells (HMEC-1) and further fractionated to isolate the active compounds.
A New Regio- and Stereo-selective Functionalization of Allylic and Homoallylic Alcohols
Cardillo, Giuliana,Orena, Mario,Porzi, Gianni,Sandri, Sergio
, p. 465 - 466 (1981)
A new, highly regio- and stereo-selective synthesis of cyclic iodocarbonates of allylic and homoallylic alcohols involving cyclofunctionalization of the corresponding alcohol carbonates is described.
A new coupled catalytic system for dihydroxylation of olefins by H2O2 [5]
Bergstad, Katarina,Jonsson, Sandra Y.,B?ckvall, Jan-E.
, p. 10424 - 10425 (1999)
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Lambert et al.
, p. 3619,3622 (1970)
Electrochemical Borylation of Alkyl Halides: Fast, Scalable Access to Alkyl Boronic Esters
Cao, Yangmin,Hu, Ping,Huang, Cheng,Liu, Zhao,Lu, Qingquan,Ma, Wan,Peng, Pan,Qi, Xiaotian,Wang, Bingbing
supporting information, p. 12985 - 12991 (2021/09/03)
Herein, a fast, scalable, and transition-metal-free borylation of alkyl halides (X = I, Br, Cl) enabled by electroreduction is reported. This process provides an efficient and practical access to primary, secondary, and tertiary boronic esters at a high current. More than 70 examples, including the late-stage borylation of natural products and drug derivatives, are furnished at room temperature, thereby demonstrating the broad utility and functional-group tolerance of this protocol. Mechanistic studies disclosed that B2cat2 serves as both a reagent and a cathodic mediator, enabling electroreduction of difficult-to-reduce alkyl bromides or chlorides at a low potential.
Enantiotopic Discrimination by Coordination-Desymmetrized meso-Ligands
Li, Yutang,Lidskog, Anna,Armengol-Relats, Helena,Pham, Thanh Huong,Favraud, Antoine,Nicolas, Maxime,Dawaigher, Sami,Xiao, Zeyun,Ma, Dayou,Lindb?ck, Emil,Strand, Daniel,W?rnmark, Kenneth
, p. 1575 - 1579 (2020/02/04)
The first examples of enantiopure catalysts that are chiral merely due to coordination of different metal ions at enantiotopic positions of an achiral meso-ligand are reported. These catalysts exhibit a pseudo-Cs symmetry and are able to catalyze reactions demanding simultaneous involvement of two catalytic sites. The latter was demonstrated by application in the asymmetric ring-opening of meso-epoxides.