583-60-8Relevant articles and documents
Activation of hydrogen peroxide by ionic liquids: Mechanistic studies and application in the epoxidation of olefins
Markovits, Iulius I. E.,Eger, Wilhelm A.,Yue, Shuang,Cokoja, Mirza,Muenchmeyer, Christian J.,Zhang, Bo,Zhou, Ming-Dong,Genest, Alexander,Mink, Janos,Zang, Shu-Liang,Roesch, Notker,Kuehn, Fritz E.
, p. 5972 - 5979 (2013)
Imidazolium-based ionic liquids that contain perrhenate anions are very efficient reaction media for the epoxidation of olefins with H2O 2 as an oxidant, thus affording cyclooctene in almost quantitative yields. The mechanism of this reaction does not follow the usual pathway through peroxo complexes, as is the case with long-known molecular transition-metal catalysts. By using in situ Raman, FTIR, and NMR spectroscopy and DFT calculations, we have shown that the formation of hydrogen bonds between the oxidant and perrhenate activates the oxidant, thereby leading to the transfer of an oxygen atom onto the olefin demonstrating the special features of an ionic liquid as a reaction environment. The influence of the imidazolium cation and the oxidant (aqueous H2O2, urea hydrogen peroxide, and tert-butyl hydrogen peroxide) on the efficiency of the epoxidation of cis-cyclooctene were examined. Other olefinic substrates were also used in this study and they exhibited good yields of the corresponding epoxides. This report shows the potential of using simple complexes or salts for the activation of hydrogen peroxide, owing to the interactions between the solvent medium and the active complex. Copyright
-
Takagi et al.
, p. 214 (1968)
-
Two new silver(I) complexes with 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz): Preparation, characterization, crystal structure and alcohol oxidation activity in the presence of oxone
Najafpour, Mohammad Mahdi,Ho?yn?ska, Ma?gorzata,Amini, Mojtaba,Kazemi, Sayed Habib,Lis, Tadeusz,Bagherzadeh, Mojtaba
, p. 2837 - 2843 (2010)
Two new silver(I) complexes ((tptz)Ag2(NO3) 2 and [Ag5(tptz)4](NO3)5) with 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) have been synthesized and characterized by X-ray diffraction, elemental analysis, 1H NMR, IR, fluorescence, UV-Vis spectroscopy and electrochemistry. Oxidation of alcohols to their corresponding aldehydes and ketones was conducted with one of the Ag complexes as a catalyst, soluble enough in organic solvent, using oxone (2KHSO5·KHSO4·K2SO4) as an oxidant under biphasic reaction conditions (CH2Cl 2/H2O) and tetra-n-butylammonium bromide as phase transfer agent under air at room temperature.
-
Sisti,A.J.
, p. 2670 - 2673 (1970)
-
STEREOCHEMICAL EFFECTS IN THE GAS-PHASE PINACOL REARRANGEMENT OF CIS- AND TRANS-1-METHYLCYCLOHEXANE-1,2-DIOL.
Cecchi, Patrizio,Cipollini, Romano,Pizzabiocca, Adriano,Renzi, Gabriele,Speranza, Maurizio
, p. 4847 - 4856 (1988)
The gas-phase pinacol rearrangement of cis and trans-1-methyl-1,2-cyclohexanediols, promoted by D3(+) and CnH5(+) (n= 1,2), was studied by the radiolytic method in the pressure range 100-760 Torr.Under all conditions, 2-methyl-cyclohexanone is the predominant product, arising from both substrates via different pinacol rearrangements and successive fast isomerisation of the corresponding primary intermediates, e,g, O-protonated 1-methyl-1-cyclopentanecarboxaldehyde.This conclusion is based from kinetic analysis of competition experiments with pinacol as reference substrate, carried out at high pressure (760 Torr) with or without added base (NMe3, 3 Torr), showing that the pinacol rearrngement rates are markedly dependent on the stereochemical features of the diol.Accordingly, the trans diol rearranges more rapidly than the cis isomer, which in turn isomerizes faster than pinacol, indicating that anti-periplanar CH2 migration to the vicinal tertiary C-OH2(+) center in trans (k2) is over five times faster than H migration in cis (k3).Analysis of the relative migrating ability of the different CH2 moieties in trans (k2 > k1) allowed exclusion of appreciable anchimeric assistance in these gas-phase pinacol rearrangements.The results are compared with revelant gas-phase data with those concerting the same substrates in acidic solution.
A new and highly effective method for catalytic oxidation of alcohols to the corresponding carbonyl compounds using the tris[(2-oxazolinyl)phenolato] manganese(III)/Oxone/n-Bu4NBr oxidation system
Bagherzadeh, Mojtaba
, p. 8943 - 8945 (2003)
Oxone (2KHSO5·KHSO4·K 2SO4) in the presence of mer-tris[(2-oxazolinyl)phenolato] manganese(III), Mn(phox)3, as catalyst under biphasic reaction conditions (CH2Cl2/H2O)
Reduction of nitrosoarene ligands in binuclear palladium(II) complexes
Orlova,Kazyul'kin,Shubochkin,Shishkin,Stromnova
, p. 1689 - 1692 (2001)
Reduction of the binuclear Pd11 complexes Pd2(OCOR)2(o-CH2C6H4-NO)2 (1) and Pd2(OCOR)2(o-PhN-C6H4-NO)2 (2) (where R = Me, C
Deciphering Reactivity and Selectivity Patterns in Aliphatic C-H Bond Oxygenation of Cyclopentane and Cyclohexane Derivatives
Martin, Teo,Galeotti, Marco,Salamone, Michela,Liu, Fengjiao,Yu, Yanmin,Duan, Meng,Houk,Bietti, Massimo
supporting information, p. 9925 - 9937 (2021/06/30)
A kinetic, product, and computational study on the reactions of the cumyloxyl radical with monosubstituted cyclopentanes and cyclohexanes has been carried out. HAT rates, site-selectivities for C-H bond oxidation, and DFT computations provide quantitative information and theoretical models to explain the observed patterns. Cyclopentanes functionalize predominantly at C-1, and tertiary C-H bond activation barriers decrease on going from methyl- and tert-butylcyclopentane to phenylcyclopentane, in line with the computed C-H BDEs. With cyclohexanes, the relative importance of HAT from C-1 decreases on going from methyl- and phenylcyclohexane to ethyl-, isopropyl-, and tert-butylcyclohexane. Deactivation is also observed at C-2 with site-selectivity that progressively shifts to C-3 and C-4 with increasing substituent steric bulk. The site-selectivities observed in the corresponding oxidations promoted by ethyl(trifluoromethyl)dioxirane support this mechanistic picture. Comparison of these results with those obtained previously for C-H bond azidation and functionalizations promoted by the PINO radical of phenyl and tert-butylcyclohexane, together with new calculations, provides a mechanistic framework for understanding C-H bond functionalization of cycloalkanes. The nature of the HAT reagent, C-H bond strengths, and torsional effects are important determinants of site-selectivity, with the latter effects that play a major role in the reactions of oxygen-centered HAT reagents with monosubstituted cyclohexanes.
Catalytic alcohol oxidation using cationic Schiff base manganeseIII complexes with flexible diamino bridge
Kakavand, Meysam,Mastrorilli, Piero,Mesto, Ernesto,Neshat, Abdollah,Osanlou, Farzane,Schingaro, Emanuela,Todisco, Stefano
, (2020/11/04)
Four Schiff base manganese(III) complexes with derivatives of [(R,R)-N,N’-bis(salicy1idene)-1,2-cyclohexanediaminato)] including substituents on salicylaldehyde such as 3-methoxy, 3,5-di-tert-butyl and 3,5-chloro were synthesized and characterized using a combination of IR, UV–Vis, and HR ESI-MS techniques. The catalytic activity of these complexes was tested in the oxidation of 1-phenylethanol to acetophenone, revealing very good performances for all of the four manganese complexes. The catalytic reactions were carried out in the presence of tert-butyl hydroperoxide (TBHP) as oxidant and imidazole as co-catalyst. Complex Mn-4, bearing electron withdrawing [(R,R)-N,N’-bis(3,5-di-chloro-salicylidene)-1,2-cyclohexanediaminato)] ligand was found to be the most stable of the tested Mn(III) complexes and was selected for the oxidation of several primary and secondary alcohols.