- Photo-Induced Dihydroxylation of Alkenes with Diacetyl, Oxygen, and Water
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Herein reported is a photo-induced production of vicinal diols from alkenes under mild reaction conditions. The present dihydroxylation method using diacetyl (= butane-2,3-dione), oxygen, and water dispenses with toxic reagents and intractable waste generation.
- Masuda, Yusuke,Ikeshita, Daichi,Murakami, Masahiro
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- Preparation of Highly Active Monometallic Rhenium Catalysts for Selective Synthesis of 1,4-Butanediol from 1,4-Anhydroerythritol
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1,4-Butanediol can be produced from 1,4-anhydroerythritol through the co-catalysis of monometallic mixed catalysts (ReOx/CeO2+ReOx/C) in the one-pot reduction with H2. The highest yield of 1,4-butanediol was over 80 %, which is similar to the value obtained over ReOx–Au/CeO2+ReOx/C catalysts. Mixed catalysts of CeO2+ReOx/C showed almost the same performance, giving 89 % yield of 1,4-butanediol. The reactivity trends of possible intermediates suggest that the reaction mechanism over ReOx/CeO2+ReOx/C is similar to that over ReOx–Au/CeO2+ReOx/C: deoxydehydration (DODH) of 1,4-anhydroerythritol to 2,5-dihydrofuran over ReOx species on the CeO2 support with the promotion of H2 activation by ReOx/C, isomerization of 2,5-dihydrofuran to 2,3-dihydrofuran catalyzed by ReOx on the C support, hydration of 2,3-dihydrofuran catalyzed by C, and hydrogenation to 1,4-butanediol catalyzed by ReOx/C. The reaction order of conversion of 1,4-anhydroerythritol with respect to H2 pressure is almost zero and this indicates that the rate-determining step is the formation of 2,5-dihydrofuran from the coordinated substrate with reduced Re in the DODH step. The activity of ReOx/CeO2+ReOx/C is higher than that of ReOx–Au/CeO2+ReOx/C, which is probably related to the reducibility of ReOx/C and the mobility of the Re species between the supports. High-valent Re species such as Re7+ on the CeO2 and C supports are mobile in the solvent; however, low-valent Re species, including metallic Re species, have much lower mobility. Metallic Re and cationic low-valent Re species with high reducibility and low mobility can be present on the carbon support as a trigger for H2 activation and promoter of the reduction of Re species on CeO2. The presence of noble metals such as Au can enhance the reducibility through the activation of H2 molecules on the noble metal and the formation of spilt-over hydrogen over noble metal/CeO2, as indicated by H2 temperature-programmed reduction. The higher reducibility of ReOx–Au/CeO2 lowers the DODH activity of ReOx–Au/CeO2+ReOx/C in comparison with ReOx/CeO2+ReOx/C by restricting the movement of Re species from C to CeO2.
- Wang, Tianmiao,Tamura, Masazumi,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 3615 - 3626
(2019/07/15)
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- Selective transition-metal-free vicinal cis-dihydroxylation of saturated hydrocarbons
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A transition-metal-free cis-dihydroxylation of saturated hydrocarbons under ambient reaction conditions has been developed. The described approach allows a direct and selective synthesis of vicinal diols. The new reaction thereby proceeds via radical iodination and a sequence of oxidation steps. A broad scope of one-pot dual C(sp3)-H bond functionalization for the selective synthesis of vicinal syn-diols was demonstrated.
- Bering, Luis,Antonchick, Andrey P.
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p. 452 - 457
(2016/12/30)
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- Bronsted acid-catalyzed dihydroxylation of olefins in aqueous medium
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The trans-dihydroxylation of olefins occurs efficiently by aqueous hydrogen peroxide catalyzed by p-toluenesulfonic acid at 50°C, allowing the catalyst reuse and an outstanding substrate functional group tolerance such as tert-butoxycarbonylamino (BocNH), benzyloxycarbonylamino (CbzNH), benzyloxy (OBn), tosyloxy (OTs), hindered ketal, (2-trimethylsilyl)ethoxymethoxy (OSEM), benzylamino (NBz), benzyloxy (OBz) and free amino acid. Copyright
- Rosatella, Andreia A.,Afonso, Carlos A.M.
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supporting information; experimental part
p. 2920 - 2926
(2012/01/03)
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- Hot water-promoted ring-opening of epoxides and aziridines by water and other nucleopliles
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Effective hydrolysis of epoxides and aziridines was conducted by heating them in water at 60 or 100 °C. Other types of nucleophile such as amines, sodium azide, and thiophenol could also efficiently open epoxides and aziridines in hot water. It was proposed that hot water acted as a modest acid catalyst, reactant, and solvent in the hydrolysis reactions.
- Wang, Zhi,Cui, Yong-Tao,Xu, Zhao-Bing,Qu, Jin
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p. 2270 - 2274
(2008/09/19)
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- Carbon tetrabromide: An efficient catalyst for regioselective ring opening of epoxides with alcohols and water
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Epoxides undergo rapid ring opening with a range of alcohols in the presence of catalytic amount of carbon tetrabromide under mild and convenient conditions to afford the corresponding β-alkoxy alcohols and 1,2-diols in high yields with high regioselectivity. Georg Thieme Verlag Stuttgart.
- Yadav,Reddy,Harikishan,Madan,Narsaiah
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p. 2897 - 2900
(2007/10/03)
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- Tetrabutylammonium bisulfate: A new effective catalyst for the hydrolysis of aziridines or epoxides
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Bu4NHSO4 (TBAHS) is an effective catalyst for the hydrolysis of aziridines and epoxides under mild and non-metal conditions to give the corresponding β-amino alcohols and 1,2-diols in high yields. The catalyst can be recycled.
- Fan, Ren-Hua,Hou, Xue-Long
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p. 1565 - 1567
(2007/10/03)
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- One-Pot and Stereospecific Synthesis of cis-1,2-Diazides via Mitsunobu Reaction of Epoxides
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Mitsunobu reaction of epoxides using hydrazoic acid, diethylazodicarboxylate, and triphenylphosphine as reagents gave the corresponding cis-1,2-diazides in moderate yield. Application of similar reaction conditions to trans-diols furnished the corresponding trans-1,2-diazides.
- Goeksu, Sueleyman,Secen, Hasan,Suetbeyaz, Yasar
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p. 2373 - 2378
(2007/10/03)
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- Diastereoselective inter- and intramolecular pinacol coupling of aldehydes promoted by monomeric titanocene(III) complex Cp2TiPh
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A monomeric titanocene(III) derivative, Cp2TiPh, effectively promoted the pinacol coupling of both an aromatic aldehyde, benzaldehyde, and an aliphatic aldehyde, 3-phenylpropionaldehyde. The same reactive complex was successfully generated by a catalytic amount of a precursor, Cp2Ti(Ph)Cl, and its stoichiometric amount of Zn. The Cp2TiPh-catalyzed pinacol coupling of benzaldehyde derivatives and aliphatic aldehydes afforded the corresponding 1,2-diols in high yields with moderate to good threo-selectivity. On the other hand, Cp2TiPh-catalyzed pinacol-cyclization of dials gave cyclic 1,2-diols with excellent diastereoselectivity. The extension of this protocol to chiral dials demonstrated that the phenyltitanium complex catalytically transmitted an axial chirality or a central, chirality of the starting dials to the central chirality of the resultant 1,2-diols.
- Yamamoto,Hattori,Miwa,Nakagai,Kubota,Yamamoto,Okamoto,Itoh
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p. 3865 - 3870
(2007/10/03)
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- Selective oxidation of cyclopentene to glutaraldehyde by H2O2 over the WO3/SiO2 catalyst
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A novel WO3/SiO2 was prepared by incipient wetness impregnation of the SiO2 support synthesized by the xerogel method with the W-containing salt solution. The as-prepared WO3/SiO2 catalyst exhibited a very high yield of glutaraldehyde in the liquid phase cyclopentene oxidation by aqueous H2O2 and the leach of WO3 species during the reaction could be neglected. As a heterogeneous catalyst, it seems more suitable for the industrial process than those homogeneous catalysts owing to its easy separation from reaction products, which makes it possible to use the catalyst repetitively. According to the XRD patterns, the WO3 was present in amorphous state due to its high dispersion on the SiO2 support. These amorphous WO3 species were proved to be the active sites since the crystallization at high temperature caused a considerable deactivation. The lifetime of the catalyst was measured and its regeneration method was proposed. Effects of various factors on the catalytic behaviors, such as the WO3 loading, the calcination temperature, and the reaction media, were also investigated and discussed based on the characterizations of BET, XRD, DSC, TEM, EXAFS, and Raman spectra.
- Jin, Ronghua,Li, Hexing,Deng, Jing-Fa
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- Iron(III) trifluoroacetate as an efficient catalyst for solvolytic and nonsolvolytic nucleophilic ring opening of epoxides
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Iron(III) trifluoroacetate was used as an efficient and nonhygroscopic catalyst for the alcoholysis, hydrolysis, and acetolysis of epoxides. The addition of chloride, bromide, iodide, and nitrate ions to epoxides to produce the corresponding 2-halo and 2-nitratoalkanols and also the conversion of epoxides to acetonides and thiiranes were also performed efficiently in the presence of this catalyst.
- Iranpoor, Nasser,Adibi, Hadi
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p. 675 - 680
(2007/10/03)
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- Highly trans-selective intramolecular pinacol coupling of dials catalyzed by bulky Cp2TiPh
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Cp2Ti(Ph)Cl in the presence of Me3SiCl and Zn provides an effective pinacol coupling catalyst for aromatic and aliphatic aldehydes.
- Yamamoto, Yoshihiko,Hattori, Reiko,Itoh, Kenji
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p. 825 - 826
(2007/10/03)
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- Ion Exchange Resin-Mediated Hydrolytic Cleavage of Epoxides. Simple One-Pot Synthesis of 2-Arylketones from 1-Aryl-1,2-epoxides
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Epoxides are cleaved in an aqueous solution with Dowex-50W.Alicyclic epoxides are converted to trans-1,2-diols whereas 1-aryl-1,2-epoxides furnish 2-arylketones in excellent yields.
- Ranu, Brindaban C.,Chakraborty, Rupak
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p. 1751 - 1756
(2007/10/02)
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- A Convenient Catalytic Method for the Dihydroxylation of Alkenes by Hydrogen Peroxide
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A simple method for preparing water-soluble vicinal diols from the corresponding water-insoluble alkenes is reported.It is based on the use of tungsten peroxo complexes as catalysts and hydrogen peroxide as the oxidizing agent in a two-phase system.
- Venturello, Carlo,Gambaro, Mario
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p. 295 - 297
(2007/10/02)
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- ONE-POT TWO-STEP SYNTHESIS OF 1,2-DIOL
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Diols can be prepared by hydroxilation of alkenes with m-chloroperoxybenzoic acid in water.The process occurs with high yield and complete anti stereospecificity.
- Fringuelli, F.,Germani, R.,Pizzo, F.,Savelli, G.
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p. 1939 - 1944
(2007/10/02)
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- Reactions of the Trimethylsilyl Ion with 1,2-Cyclopentanediol Isomers in the Collision Region of a Triple Quadrupole Instrument
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Ion-molecule reactions with the trimethylsilyl ion were used to distinguish between cis- and trans-1,2-cyclopentanediol isomers.The ion kinetic energy of + was varied from 0 eV to 15 eV (center of mass frame of reference).At low ion kinetic energies (+.The cis-1,2-cyclopentanediol isomer favors decomposition of + to yield the hydrated trimethylsilyl ion + at m/z 91.For the trans isomer, the formation of the hydrated trimethylsilyl ion is an endethermic process with a definite threshold ion kinetic energy.
- Meyerhoffer, William J.,Bursey, Maurice M.
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p. 246 - 252
(2007/10/02)
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- THE PREPARATION AND PROPERTIES OF NEUTRAL DIAMIDE IONOPHORES FOR GROUP IIA METAL CATIONS-II
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The elaboration of a series of neutral ligands featuring vicinal ether and N,N-dialkylacetamido groups is described.Several of these ligands were previously described.The ligands are moderate binders with Kapp=1E3-1E5 in methanol of the Group IIA cations for wich they are sensitive.Binding constants by Scatchard method are reported for number of ligands mainly with Ca, Sr, Mn and Ba.The ligands in methylene chloride solution extract these cations via their picrate salts from water.The electrochemical Kijpot (selectivity) values for some of the ligands when they are incorporated into liquid membrane electrodes and tested with various cations as determined by Simon et al. (ETH Zurich) are reported.Selectivity ratios of over 100:1 for Na vs Ca were found for several piperidenyl amides of 1,2-phenylenedioxydiacetic acid.Incorporation of N-methylamino instead of ether oxygen groups into the basic structure gives a stronger cation binder which is still selective for Group IIA vs Group IA cations but with binding capacity for transition metal cations also.Limitations of the Scatchard plots for these ligands and the non-correspondance of electrochemical selectivities with the ordering of binding of cations in single liquid phase are discussed.
- Borowitz, Irving J.,Readio, Josephine D.,Li, Ven-Shun
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p. 1009 - 1016
(2007/10/02)
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- Vinyl Epoxide Hydrolysis Reactions
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The rates of hydrolysis of cyclopentadiene oxide (3), cyclohexadiene oxide (4), cycloheptadiene oxide (5), cyclooctadiene oxide (6), butadiene oxide (7), and styrene oxide (8) have been determined as a function of pH.Each epoxide exhibited acid-catalyzed hydrolysis at low pH, and 3-5 showed significant rates for "spontaneous" reaction with solvent at intermediate pH values.The hydrolyses of several of the vinyl epoxides (4 and 5) showed kinetic terms in HO- at pH > ca. 13.Specific chloride effects attributed to nucleophilic addition of Cl- to neutral epoxide were observed for those compounds (3, 4, and 8) hydrolyzed in KCl solutions.From kinetic and product studies, mechanisms for hydrolyses of the vinyl epoxides are postulated.Acid-catalyzed hydrolyses of 3, 4, 5, and 6 were found to be A-1 in nature, proceeding via intermediate allyl cations.Product distributions depended on the structure of the cation.Mechanisms and product distributions for the spontaneous hydrolyses of vinyl epoxides were found to be variable, and dependent on the structure of the epoxide.
- Ross, Angela M.,Pohl, Terese M.,Piazza, Kathryn,Thomas, Michael,Fox, Bonnie,Whalen, Dale L.
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p. 1658 - 1665
(2007/10/02)
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- Oxidation by Cobalt(III) Acetate. Part 4. Kinetics and Mechanism of the Oxidation of Glycols in Acetic Acid
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The oxidative cleavage of 1,2-glycols by cobalt(III) acetate in acetic acid was studied kinetically in order to clarify the reaction mechanism.The rates were first-order in both cobalt(III) acetate and substrate for the oxidation of all the diols used. cis-Cyclopentane-1,2-diol and decalin-9,10-diol were more rapidly oxidized than the corresponding trans-isomers, respectively, whereas cis-cyclohexane-1,2-diol was more slowly oxidized than the trans-isomer.The oxidation of trans-2-methoxycyclohexanol was much slower than that of the corresponding diol.The mechanism involving the formation of a bidentate complex between cobalt(III) acetate dimer and glycol is discussed.
- Morimoto, Takashi,Hirano, Masao
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p. 1087 - 1090
(2007/10/02)
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