- CoII Immobilized on Aminated Magnetic-Based Metal–Organic Framework: An Efficient Heterogeneous Nanostructured Catalyst for the C–O Cross-Coupling Reaction in Solvent-Free Conditions
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Abstract: In this paper, we report the synthesis of Fe3O4?AMCA-MIL53(Al)-NH2-CoII NPs based on the metal–organic framework structures as a magnetically separable and environmentally friendly heterogeneous nanocatalyst. The prepared nanostructured catalyst efficiently promotes the C–O cross-coupling reaction in solvent-free conditions without the need for using toxic solvents and/or expensive palladium catalyst. Graphic Abstract: [Figure not available: see fulltext.].
- Mohammadinezhad, Arezou,Akhlaghinia, Batool
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p. 332 - 352
(2020/01/11)
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- Copper Catalyzed sp3 C-H Etherification with Acyl Protected Phenols
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A variety of acyl protected phenols AcOAr participate in sp3 C-H etherification of substrates R-H to give alkyl aryl ethers R-OAr employing tBuOOtBu as oxidant with copper(I) β-diketiminato catalysts [CuI]. Although 1°, 2°, and 3° C-H bonds may be functionalized, selectivity studies reveal a preference for the construction of hindered, 3° C-OAr bonds. Mechanistic studies indicate that β-diketiminato copper(II) phenolates [CuII]-OAr play a key role in this C-O bond forming reaction, formed via transesterification of AcOAr with [CuII]-OtBu intermediates generated upon reaction of [CuI] with tBuOOtBu.
- Salvador, Tolani K.,Arnett, Charles H.,Kundu, Subrata,Sapiezynski, Nicholas G.,Bertke, Jeffery A.,Raghibi Boroujeni, Mahdi,Warren, Timothy H.
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supporting information
p. 16580 - 16583
(2017/01/10)
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- Tetrabutyl ammonium bromide-mediated benzylation of phenols in water under mild condition
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Benzylation of phenol was successfully achieved in water under room temperature mediated by tetrabutylammonium bromide (TBAB) for only 2 h affording the corresponding benzyl phenyl ether with good to excellent yields. This protocol is very efficient, simple, avoiding catalysts, easy to work-up after reaction, and especially 'green'.
- Wang, Hailei,Ma, Yuping,Tian, Heng,Yu, Ajuan,Chang, Junbiao,Wu, Yangjie
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p. 2669 - 2673
(2014/04/03)
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- A PEG1000-DAIL[CdCl3]-toluene temperature-dependent biphasic system that regulates homogeneously catalyzed C-O coupling of organic halides with phenols and alcohols under ligand-free conditions
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An efficient, experimentally simple, and convenient procedure for the C-O coupling of organic halides with phenols and alcohols in a PEG 1000-DAIL[CdCl3]-toluene temperature-dependent biphasic system has been developed. The product can be easily isolated by a simple decantation, and the catalytic system can be recycled and reused without loss of catalytic activity.
- Hu, Yu Lin,Ma, Xiao Yun,Lu, Ming
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experimental part
p. 471 - 480
(2011/06/22)
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- Ionic liquids as reagent and reaction medium: Preparation of alkyl aryl ethers
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Room temperature ionic liquid, [bmIm]OH, is used as a green recyclable reaction medium and reagent for the alkylation of phenols in excellent yields. The recovered ionic liquid was reused five to six times with consistent activity.
- Mohanazadeh, Farajollah,Aghvami, Majid
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- Isotope effects in nucleophilic substitution reactions X. The effect of changing the nucleophilic atom on ion-pairing in an S(N)2 reaction
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The effect of ion-pairing in an S(N)2 reaction is very different when the nucleophilic atom is changed from sulfur to oxygen, i.e., changing the nucleophile from thiophenoxide ion to phenoxide ion. When the nucleophile is sodium thiophenoxide, ion-pairing markedly alters the secondary α-deuterium kinetic isotope effect (transition state structure) and the substituent effect found by changing the para substituent on the nucleophile. When the nucleophile is sodium phenoxide, ion-pairing does not significantly affect the secondary α-deuterium or the chlorine leaving group kinetic isotope effects (transition state structure) or the substituent effects found by changing a para substituent on the nucleophile or the substrate. The different effects of ion-pairing may occur because the electron density on the hard oxygen atom of the sodium phenoxide is not affected significantly by ion-pairing.
- Fang, Yao-Ren,Lai, Zhu-Gen,Westaway, Kenneth Charles
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p. 758 - 764
(2007/10/03)
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- Organic reactions catalyzed by methylrhenium trioxide: Dehydration, amination, and disproportionation of alcohols
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Methylrhenium trioxide (MTO) is the first transition metal complex in trace quantity to catalyze the direct formation of ethers from alcohols. The reactions are independent of the solvents used: benzene, toluene, dichloromethane, chloroform, acetone, and in the alcohols themselves. Aromatic alcohols gave better yields than aliphatic. Reactions between two different alcohols could also be used to prepare unsymmetric ethers, the best yields being obtained when one of the alcohols is aromatic. MTO also catalyzes the dehydration of alcohols to form olefins at room temperature, aromatic alcohols proceeding in better yield. When primary (secondary) amines were used as the limiting reagent, direct amination of alcohols catalyzed by MTO gave good yields of the expected secondary (tertiary) amines at room temperature. Disproportionation of alcohols to alkanes and carbonyl compounds was also observed for aromatic alcohols in the presence of MTO. On the basis of the results of this investigation and a comparison with the interaction between MTO and water, a concerted process and a mechanism involving carbocation intermediates have been suggested.
- Zhu, Zuolin,Espenson, James H.
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p. 324 - 328
(2007/10/03)
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- Substituent Dependence of the ?-Acceptor Induced Bond Cleavage Reactions of Benzyl Phenyl Ethers
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The relative C-O bond cleavage reaction rates (krel) of eight substituted benzyl phenyl ethers (BPE's) have been measured.These C-O bond cleavage reactions were thermally initiated by 2,3-dichloro-5,6-dicyanoquinone (DDQ).The equilibrium constants (K) for charge-transfer complex formation of these BPE's with the electron acceptors DDQ and TCNE in the solvent methylene chloride have also been determined at room temperature.The best correlation of log krel for DDQ reactions has been observed in these reactions.From this data, hydride transfer to DDQ is the rate-determining step of the reaction.
- Penn, John H.,Lin, Zhe
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p. 1554 - 1559
(2007/10/02)
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