- Structural studies of a novel bioactive benzophenone derivative: (4-Chloro-2-hydroxy-phenyl)-phenyl-methanone
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The title compound (4-Chloro-2-hydroxy-phenyl)-phenyl-methanone was synthesized and the product obtained was characterized by spectroscopic techniques, and finally the structure was confirmed by X-ray diffraction studies. The compound crystallizes in the orthorhombic crystal system with the space group Pbca with unit cell parameters, a = 14.0359(5) ?, b = 6.8084(3) ?, c = 23.1097(8) ?, and Z = 4. The structure exhibits an intramolecular hydrogen bond which closes an S(6) ring. No directional interactions beyond the van der Waals packing contacts were identified in the crystal structure.
- Zabiulla,Naveen,Begum, A. Bushra,Khanum, Shaukath Ara,Lokanath
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Read Online
- Mechanically induced solvent-free esterification method at room temperature
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Herein, we describe two novel strategies for the synthesis of esters, as achieved under high-speed ball-milling (HSBM) conditions at room temperature. In the presence of I2 and KH2PO2, the reactions afford the desired esterification derivatives in 45% to 91% yields within 20 min of grinding. Meanwhile, using KI and P(OEt)3, esterification products can be obtained in 24% to 85% yields after 60 min of grinding. In addition, the I2/KH2PO2 protocol was successfully extended to the late-stage diversification of natural products showing the robustness of this useful approach. Further application of this method in the synthesis of inositol nicotinate was also discussed. This journal is
- Zheng, Lei,Sun, Chen,Xu, Wenhao,Dushkin, Alexandr V.,Polyakov, Nikolay,Su, Weike,Yu, Jingbo
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p. 5080 - 5085
(2021/02/05)
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- Substituent and Surfactant Effects on the Photochemical Reaction of Some Aryl Benzoates in Micellar Green Environment?
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In this study, we carried out preparative and mechanistic studies on the photochemical reaction of a series of p-substituted phenyl benzoates in confined and sustainable micellar environment. The aim of this work is mainly focused to show whether the nature of the surfactant (ionic or nonionic) leads to noticeable selectivity in the photoproduct formation and whether the electronic effects of the substituents affect the chemical yields and the rate of formation of the 5-substituted-2-hydroxybenzophenone derivatives. Application of the Hammett linear free energy relationship (LFER) on the rate of formation of benzophenone derivatives, on the lower energy band of the UV-visible absorption spectra of the aryl benzoates and 5-substituted-2-hydroxybenzophenone derivatives allows a satisfactory quantification of the substituent effects. Furthermore, UV-visible and 2D-NMR (NOESY) spectroscopies have been employed to measure the binding constant Kb and the location of the aryl benzoates within the hydrophobic core of the micelle. Finally, TD-DFT calculations have been carried out to estimate the energies of the absorption bands of p-substituted phenyl benzoates and 5-substituted-2-hydroxybenzophenone derivatives providing good linear correlation with those values measured experimentally.
- Siano, Gastón,Crespi, Stefano,Bonesi, Sergio M.
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p. 1298 - 1309
(2021/05/07)
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- Hydrogen-bond-assisted transition-metal-free catalytic transformation of amides to esters
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The amide C-N cleavage has drawn a broad interest in synthetic chemistry, biological process and pharmaceutical industry. Transition-metal, luxury ligand or excess base were always vital to the transformation. Here, we developed a transition-metal-free hydrogen-bond-assisted esterification of amides with only catalytic amount of base. The proposed crucial role of hydrogen bonding for assisting esterification was supported by control experiments, density functional theory (DFT) calculations and kinetic studies. Besides broad substrate scopes and excellent functional groups tolerance, this base-catalyzed protocol complements the conventional transition-metal-catalyzed esterification of amides and provides a new pathway to catalytic cleavage of amide C-N bonds for organic synthesis and pharmaceutical industry. [Figure not available: see fulltext.]
- Huang, Changyu,Li, Jinpeng,Wang, Jiaquan,Zheng, Qingshu,Li, Zhenhua,Tu, Tao
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- Synthesis of cycloalkyl/steroidal heteroaryl sulfides using rhodium-catalyzed heteroaryl exchange reaction
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Cycloalkyl heteroaryl sulfides are efficiently synthesized by the single-bond cleavage and exchange reaction of S-cycloalkyl thioesters and heteroaryl ethers without using a base. The method is applicable to steroids at the A- and D-rings, and provides diverse heteroarylthiolated steroids with five- and six-membered heteroarenes.
- Arisawa, Mieko,Nakai, Katsuya,Suzuki, Ren,Yamada, Tomoki,Yamaguchi, Masahiko
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p. 104 - 118
(2020/01/28)
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- Dual aminoquinolate diarylboron and nickel catalysed metallaphotoredox platform for carbon-oxygen bond construction
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Herein, aminoquinolate diarylboron complexes are utilized as photocatalysts in dual Ni/photoredox catalyzed carbon-oxygen construction reactions. Via this unified metallaphotoredox platform, diverse (hetero)aryl halides can be conveniently coupled with acids, alcohols and water. This method features operational simplicity, broad substrate scope and good compatibility with functional groups. This journal is
- Day, Craig,Jia, Xin,Wei, Lanfeng,Xu, Liang,Zu, Weisai
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supporting information
p. 8273 - 8276
(2020/08/17)
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- Base-Promoted Amidation and Esterification of Imidazolium Salts via Acyl C-C bond Cleavage: Access to Aromatic Amides and Esters
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Imidazolium salts have been effectively employed as suitable acyl transfer agents in amidation and esterification in organic synthesis. The weak acyl C(O)-C imidazolium bond was exploited to generate acyl electrophiles, which further react with amines and alcohols to afford amides and esters. The broad substrate scope of anilines and benzylic amines and base-promoted conditions are the benefits of this route. Interestingly, phenol, benzylic alcohols, and a biologically active alcohol can also be subjected to esterification under the optimized conditions.
- Karthik, Shanmugam,Muthuvel, Karthick,Gandhi, Thirumanavelan
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p. 738 - 751
(2019/01/24)
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- Oxime palladacycle in PEG as a highly efficient and recyclable catalytic system for phenoxycarbonylation of aryl iodides with phenols
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In this report, we have developed a sustainable protocol for the synthesis of aromatic esters by a carbonylative method using di-μ-chlorobis [5-hydroxy-2-[1-(hydroxyimino-?N) ethyl] phenyl-?C] palladium (II) dimer (1) catalyst in PEG-400 as a greener and recyclable solvent. The reaction is carried out at room temperature using CO in a balloon. Good to excellent yield of various esters can be synthesize using this protocol. Direct insertion of CO moiety leads to the high atom and step economy. Compared to previous protocol this phosphine free approach for the synthesis of aromatic esters provides high Turnover Number (TON) and Turnover Frequency (TOF). Developed approach has an alternative route for use of conventional palladium precursor with high conversion and selectivity. The catalyst system and product can easily be separated using diethyl ether as a solvent. The Pd/PEG-400 system could be reused up to a fifth consecutive cycle without any loss of its activity and selectivity.
- Gaikwad, Vinayak V.,Bhanage, Bhalchandra M.
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- Nickel-Catalyzed Cross-Coupling of Aryl Redoxactive Esters with Aryl Zinc Reagents
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A nickel-catalyzed aryl-aroyloxyl C(sp2)-O radical cross-coupling reaction conducted using a redox active ester with aryl zinc reagent was developed. This method demonstrates a new disconnection approach for formation of aryl aryl esters. In the one-pot sequential process, the readily available aryl carboxylic acids can be converted into functionalized aryl aryl esters and heteroaryl esters. This protocol is amenable to the gram-scale synthesis. The present method has a wide substrate scope and high functional group tolerance.
- Shih, Bo-Hao,Basha, R. Sidick,Lee, Chin Fa
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p. 8862 - 8866
(2019/09/30)
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- Transesterification of (hetero)aryl esters with phenols by an Earth-abundant metal catalyst
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Readily available and inexpensive Earth-abundant alkali metal species are used as efficient catalysts for the transesterification of aryl or heteroaryl esters with phenols which is a challenging and underdeveloped transformation. The simple conditions and the use of heterogeneous alkali metal catalyst make this protocol very environmentally friendly and practical. This reaction fills in the missing part in transesterification reaction of phenols and provides an efficient approach to aryl esters, which are widely used in the synthetic and pharmaceutical industry.
- Chen, Jianxia,Namila,Bai, Chaolumen,Baiyin, Menghe,Agula, Bao,Bao, Yong-Sheng
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p. 25168 - 25176
(2018/07/29)
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- Practical and efficient synthesis of hydroxyaryl ketones catalyzed by HF@SiO2 under solvent-free condition
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A wide variety of hydroxyaryl ketones bearing different motifs was successfully synthesized with good yields and excellent selectivities in the presence of HF@SiO2 as an environmental friendly acid under solvent-free condition. Mild and green reaction conditions and excellent yields (50-91%) make this method an attractive method for the efficient synthesis of hydroxyaryl ketones. Fries rearrangement of phenyl benzoate in the presence of HF@SiO2 led to p-hydroxybenzophenone, while phenyl acetate in the same conditions produced o-hydroxyacetophenone as a single isomer.
- Paghandeh, Hossein,Saeidian, Hamid,Ghaffarzadeh, Mohammad
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p. 809 - 814
(2018/09/26)
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- Rhodium-catalysed aryloxycarbonylation of iodo-aromatics by 4-substituted phenols with carbon monoxide or paraformaldehyde
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Rhodium-catalysed phenoxycarbonylation of aryl iodides were carried out under carbon-monoxide atmosphere and in the absence of CO, using paraformaldehyde as an alternative surrogate for carbonylation reactions. Both strategies proved to be efficient for the synthesis of the corresponding phenyl esters. High pressure reactions provided the ester products with good selectivity, however lower activity was achieved compared to palladium containing systems. Using paraformaldehyde as carbon-monoxide source special reaction conditions are required, thus dramatic changes observed during optimisation reactions. Using in situ generated Rh-diphosphine catalyst systems, remarkable influence of ligand structure and solvent composition was observed on the activity and chemoselectivity. The substrate scope and the substituent effect were also investigated.
- Seni, Anas Abu,Kollár, László,Mika, László T.,Pongrácz, Péter
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- Catalytic method for the synthesis of C-N-linked BI(HETEROARYL)S using heteroaryl ethers and N -Benzoyl heteroarenes
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C-N-linked bi(heteroaryl)s are synthesized by a rhodium-catalyzed N-heteroarylation reaction of N-benzoyl heteroarenes including azoles/azolones, pyridones, cyclic ureas, and cyclic imides using heteroaryl aryl ethers. The reaction involves the covalent bond-exchange reaction of N-CO and HetAr-O bonds without using metal bases and exhibits a broad applicability, giving diverse C-N-linked bi(heteroaryl)s containing five- and six-membered heteroarenes. The N-heteroarylation of N-H azoles/azolones and pyridone proceeds at higher reaction temperatures.
- Tanii, Saori,Arisawa, Mieko,Tougo, Takaya,Yamaguchi, Masahiko
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p. 1756 - 1759
(2018/04/14)
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- Electrodimerization of N-Alkoxyamides for Zinc(II) Catalyzed Phenolic Ester Synthesis under Mild Reaction Conditions
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An electrochemical On-Off method for phenolic ester synthesis from N-alkoxyamides has been reported. This one-pot protocol begins with rapid and selective electrodimerization of the amide using n-Bu4NI (TBAI) as an electrocatalyst. The reaction proceeds further in the absence of current via Zn catalyzed C?N bond activation of the amide dimer followed by its coupling with phenol to form the ester. The present methodology is ligand-free and takes place under mild reaction conditions. This transformation incorporates a wide variety of phenols and amide substrates leading to the formation of functionalized esters highlighting its versatility. (Figure presented.).
- Subramanian, Kripa,Yedage, Subhash L.,Bhanage, Bhalchandra M.
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p. 2511 - 2521
(2018/05/14)
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- Series of high spin mononuclear iron(III) complexes with Schiff base ligands derived from 2-hydroxybenzophenones
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The reaction of various phenols with benzoyl chloride afforded the derivatives of phenyl benzoate that subsequently underwent Fries rearrangement. The obtained 2-hydroxybenzophenone analogues were combined with linear aliphatic triamines, which afforded pentadentate Schiff base ligands. Moreover, nine new iron(iii) complexes with the general formula [Fe(Ln)X] (where, Ln is the dianion of the pentadentate Schiff base ligand, N,N′-bis((2-hydroxy-5-methylphenyl)phenyl)methylidene-1,5-diamino-3-azapentane = H2L1, N,N′-bis((2-hydroxy-3,5-dimethylphenyl)phenyl)methylidene-1,5-diamino-3-azapentane = H2L2, N,N′-bis((2-hydroxy-5-chlorophenyl)phenyl)methylidene-1,5-diamino-3-azapentane = H2L3, N,N′-bis((2-hydroxy-4-methylphenyl)phenyl)methylidene-1,5-diamino-3-azapentane = H2L4, N,N′-bis((2-hydroxy-5-bromophenyl)phenyl)methylidene-1,7-diamino-4-azaheptane = H2L5, N,N′-bis((2-hydroxy-5-bromophenyl)phenyl)methylidene-1,7-diamino-4-methyl-4-azaheptane = H2L6 and X is the chlorido, azido or isocyanato terminal ligand) were synthesized and characterized via elemental analysis, and IR and UV-VIS spectroscopy; in addition, the crystal structures of all the complexes were determined by X-ray diffraction. Magnetic investigation reveals high spin state behaviour in all the reported compounds. DFT calculations and analysis of the magnetic functions allowed to extract absolute values of the zero field splitting parameters and exchange coupling constants.
- Pogány, Luká?,Moncol, Ján,Pavlik, Ján,?alitro?, Ivan
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supporting information
p. 5904 - 5915
(2017/07/10)
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- Method of converting amide and urea into ester
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The invention provides a method of converting amide and urea into ester. In the method, different types of amide and urea are used as substrate, alcohol or phenol is used as nucleophile, iron salt is used as catalyst, and acid is used as additive, the conversion of amide and urea into ester is achieved under a mild condition. The method is characterized in that cheap iron salt is used as the catalyst, the commercialized amide, urea, and alcohol are used as the substrate, and the conversion of amide to ester is achieved in one step. The method has the advantages that the reaction condition is mild, the raw materials are cheap and easy to obtain, the reaction substrate is wide in adaptability, the selectivity and yield of the product are very high, the product is green and environmentally friendly and the like, and the method has good prospects for industrial applications.
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Paragraph 0051-0053
(2017/08/30)
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- Thieme Chemistry Journals Awardees - Where Are They Now? Rhodium-Catalyzed Synthesis of Unsymmetric Di(heteroaryl) Ethers Using Heteroaryl Exchange Reaction
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Unsymmetric di(heteroaryl) ethers were synthesized by the rhodium-catalyzed heteroaryl exchange reaction of heteroaryl aryl ethers and heteroaryl esters at equilibrium. Diverse unsymmetric di(heteroaryl) ethers containing five- and six-membered heteroaren
- Tanii, Saori,Arisawa, Mieko,Tougo, Takaya,Horiuchi, Kiyofumi,Yamaguchi, Masahiko
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supporting information
p. 1601 - 1607
(2017/08/11)
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- Palladium-Catalyzed Oxidative Carbonylation of Aryl Hydrazines with CO and O2 at Atmospheric Pressure
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Palladium-catalyzed aerobic oxidative aminocarbonylation and alkoxycarbonylation reactions with aryl hydrazines as coupling partners have been developed. The oxidative carbonylation of aryl hydrazines proceeded smoothly at atmospheric pressure CO, employi
- Tu, Yongliang,Yuan, Lin,Wang, Tao,Wang, Changliu,Ke, Jiamei,Zhao, Junfeng
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p. 4970 - 4976
(2017/05/12)
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- Rhodium-Catalyzed Synthesis of Unsymmetric Di(heteroaryl) Sulfides Using Heteroaryl Ethers and S-Heteroaryl Thioesters via Heteroarylthio Exchange
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Unsymmetric di(heteroaryl) sulfides were synthesized by a rhodium-catalyzed heteroarylthio exchange reaction of heteroaryl aryl ethers and S-(heteroaryl) thioesters. The reaction has broad applicability, giving diverse unsymmetric di(heteroaryl) sulfides containing five- and six-membered heteroarenes. No base is required in this reaction, which has been developed by the judicious design of organic substrates.
- Arisawa, Mieko,Tazawa, Takeru,Tanii, Saori,Horiuchi, Kiyofumi,Yamaguchi, Masahiko
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p. 804 - 810
(2017/04/26)
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- One for Many: A Universal Reagent for Acylation Processes
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This work describes acylation reactions facilitated by a type of heterocycle-based acyl transfer agent, 2-acyloxypyridazinone. Reactions of 2-acyloxypyridazinone with carboxylic acids yield mixed carbonic anhydride intermediates, which are reactive and could be coupled with a wide range of substrates including acids, amines, alcohols, and thiols. The wide substrate scope, ease of operation (no additive or catalyst), storage and handling stability, and atom-efficiency from recycling the heterocycle carrier make the reported acylating agent attractive for acylation-based coupling reactions.
- Moon, Hyun Kyung,Sung, Gi Hyeon,Kim, Bo Ram,Park, Jong Keun,Yoon, Yong-Jin,Yoon, Hyo Jae
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supporting information
p. 1725 - 1730
(2016/06/09)
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- Synthesis, crystal structures and DFT calculations of two new phenol-based ester derivatives
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Two new phenol-based ester derivatives, namely C13H9ClO2 (I) and C20H14O4 (II) have been synthesized and characterized by NMR spectroscopy, single crystal X-ray diffraction and density functional theory (DFT) geometry optimization and molecular orbital calculations. Compound I crystallizes in the orthorhombic space group Pca2(1),with a = 7.6297 (5) ?, b = 5.5875 (3) ?, c = 26.1624 (12) ?, α = β = γ = 90°, V = 1115.33(11) ?3 and Z = 4. Compound II crystallizes in the triclinic space group P $βar 1$$ 1 ˉ, with a = 5.7970 (4) ?, b = 8.1366 (8) ?, c = 8.8057 (9) ?, α = 83.246 (8)°, β = 72.138 (8)°, γ = 76.696 (8)°, V = 384.22 (6) ?3 and Z = 1. Geometry optimization calculations for each compound is consistent with these observations. A comparison of the dihedral angles between mean planes of the benzene rings in the crystal with the DFT theoretical calculations and weak intermolecular hydrogen bond interactions has been included for each molecule. Electronic transitions have been predicted by DFT Molecular Orbital calculations and compared with experimental absorption spectra.
- Ganaie, Javeed A.,Kumar, Jubin,Butcher, Ray J.,Jasinski, Jerry P.,Gupta, Sushil K.
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- Fe-Catalyzed Aerobic Oxidative C-CN Bond Cleavage of Arylacetonitriles Leading to Various Esters
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Fe-catalyzed aerobic oxidative esterifications of arylacetonitriles with alcohols, tri alkoxsilanes, silicate esters, or borate esters have been developed. The acyl groups which were in situ generated via chemoselective C(CO)-CN bond cleavage were directly used as electrophiles, leading to corresponding aryl esters in good to excellent yields under molecular oxygen when attacked by alcohols or alcohol surrogates. Dioxygen serves as both oxidant and reactant in this protocol. The reaction has a very broad substrate scope. Cheap starting materials as well as environmentally benign and inexpensive iron catalyst and ideal oxidant O2 feature this transformation and make it a practical and sustainable protocol to afford esters.
- Kong, Weiguang,Li, Bingnan,Xu, Xuezhao,Song, Qiuling
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p. 8436 - 8443
(2016/09/28)
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- Palladium-catalyzed alkoxycarbonylation of aryl halides with phenols employing formic acid as the CO source
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An efficient palladium-catalyzed alkoxycarbonylation of aryl halides with phenols has been developed. Various aryl benzoates have been isolated in good to excellent yields with formic acid as the CO source. The reaction proceeds smoothly under mild conditions and good functional group tolerance was observed.
- Qi, Xinxin,Li, Chong-Liang,Jiang, Li-Bing,Zhang, Wan-Quan,Wu, Xiao-Feng
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p. 3099 - 3107
(2016/05/24)
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- Solid-Phase Benzoylation of Phenols and Alcohols in Microwave Reactor: An Ecofriendly Protocol
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An efficient solid-phase benzoylation of phenols and alcohols was developed under microwave irradiation. A stoichiometric amount of benzoyl chloride was sufficient to carry out the reaction. This benzoylation features short reaction time, good yields, and easy workup procedures. Furthermore, the scope of the reaction was extended to prepare 3,5-dinitrobenzoyl derivatives of alcohols.
- Chakraborty, Suchandra,Saha, Ahana,Basu, Kaushik,Saha, Chandan
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supporting information
p. 2331 - 2343
(2015/10/12)
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- Chemoselective C-benzoylation of phenols by using ALCl3under solvent-free conditions
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Substituted phenols were chemo-selectively reacted with benzoylchloride in presence of aluminum chloride under solvent-free condition to afford the corresponding 2′-hydroxy aryl benzophenones in excellent yields (72-96%). Naphthol benzoylation resulted in lower yields as compared to phenols. Both reactions completed in 5-10 min with quantitative yields providing excellent control over regioselectivity of products.
- Gaikwad, Sunil V.,Nawghare, Beena R.,Lokhande, Pradeep D.
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p. 319 - 325
(2015/07/27)
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- Palladium supported on triphenylphosphine functionalized porous organic polymer: A highly active and recyclable catalyst for alkoxycarbonylation of aryl iodides
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An efficient method for the alkoxycarbonylation of aryl iodides using palladium supported on triphenylphosphine functionalized porous organic polymer (Pd@KAPs(Ph-PPh3)) as the catalyst is reported. Under balloon pressure of CO, various aryl iodides on carbonylation with alcohols and phenols give the corresponding products in moderate to excellent yields (74-96%). The catalyst can be easily separated by simple filtration process and recycled up to ten times without significant decrease in activity. The salient features of this protocol are the simplicity in handling of the catalyst, low CO pressure, negligible palladium leaching and good catalyst recyclability.
- Lei, Yizhu,Wu, Linjuan,Zhang, Xuefeng,Mei, Hui,Gu, Yanlong,Li, Guangxing
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p. 164 - 169
(2015/02/19)
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- The first vinyl acetate mediated organocatalytic transesterification of phenols: A step towards sustainability
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The present report outlines our efforts toward a simple yet elegant protocol for O-acylation of a wide variety of phenols. This highly enabling and solventless method relies on vinyl acetate as an innocuous acyl donor and DABCO as an organocatalyst. Operational simplicity, excellent yields, higher and faster conversion rates without excess reagents, a simple workup and essentially no need of columns are some of the salient features of the reported protocol.
- Kumar, Manoj,Bagchi, Sourav,Sharma, Anuj
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p. 8329 - 8336
(2015/11/10)
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- Rhodium-catalyzed synthesis of unsymmetrical di(aryl/heteroaryl)methanes using aryl/heteroarylmethyl ketones via CO-C bond cleavage
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RhH(PPh3)4 and 1,2-bis(diphenylphosphino)benzene catalyze the reaction of aryl/heteroarylmethyl ketones and aryl heteroaryl ethers giving unsymmetrical diarylmethanes containing one or two heteroarenes in high yields. The reaction do
- Li, Guangzhe,Arisawa, Mieko,Yamaguchi, Masahiko
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supporting information
p. 4328 - 4330
(2014/04/17)
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- Montmorillonite K10 and KSF clays as acidic and green catalysts for effective esterification of phenols and alcohols under MWI
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Montmorillonite K-10 and KSF clays catalyze esterification of phenols and alcohols under microwave irradiation and solvent-free conditions in high yields within seconds.
- Marvi,Fekri,Takhti
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p. 1837 - 1840
(2015/01/09)
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- Catalytic application of fluorous silica gel in Fries rearrangement
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Commercially available fluorous silica gel (Fluoro Flash) with no further post-modification was successfully investigated and applied merely as a catalyst in Fries rearrangement of various aryl esters under solvent free conditions in 4 h and optimized temperatures. In addition to good yields and recyclability of the catalyst, toxicity of reaction medium, by-products, and wastes were minimized. Also, low catalyst loading was another advantage of this methodology.
- Ghaffarzadeh, Mohammad,Ahmadi, Maryam
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- Nucleophilic substitution reactions of Y-Substituted-Phenyl Benzoates with Potassium Ethoxide in Anhydrous Ethanol: Reaction Mechanism and Role of K+ Ion
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Pseudo-first-order rate constants (kobsd) have been measured spectrophotometrically for the reactions of Ysubstituted-phenyl benzoates (5a-j) with potassium ethoxide (EtOK) in anhydrous ethanol at 25.0 ± 0.1 °C. The plots of kobsd vs. [EtOK] curve upward regardless of the electronic nature of the substituent Y in the leaving group. Dissection of kobsd into the second-order rate constants for the reactions with the dissociated EtOV and ion-paired EtOK (i.e., kEtO-and kEtOK, respectively) has revealed that the ion-paired EtOK is more reactive than the dissociated Et-V. The Bronsted-type plots for the reactions with the dissociated Et-V and ion-paired EtOK exhibit highly scattered points with βlg = -0.5 ± 0.1. The Hammett plots correlated with ao constants result in excellent linear correlations, indicating that no negative charge develops on the O atom of the leaving Ysubstituted-phenoxide ion in transition state. Thus, it has been concluded that the reactions with the dissociated EtOV and ion-paired EtOK proceed through a stepwise mechanism, in which departure of the leaving group occurs after the RDS, and that K+ ion catalyzes the reactions by increasing the electrophilicity of the reaction center through a four-membered cyclic TS structure.
- Kim, Song-I,Cho, Hyo-Jin,Um, Ik-Hwan
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p. 177 - 181
(2014/02/14)
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- Alkoxycarbonylation and phenoxycarbonylation reactions catalyzed by a palladium(II) organometallic complex encaged in y zeolite
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Catalytic routes for synthesis of alkyl benzoates by alkoxycarbonylation reactions and aryl benzoates by phenoxycarbonylation reactions of aryl iodides are described using a palladium-1,10-phenanthroline complex encaged in Y zeolite. Moderate to excellent yields (40-99 %) of various benzoates were obtained at low Pd loadings of 0.6 mol%. The catalyst could be effectively removed from the reaction mixture by a simple filtration process and was reused four times with only minor loss of activity. Furthermore, its catalytic activity was further highlighted by a comparison with another two supported Pd catalysts. The protocol has the advantages of easy handing, moderate to excellent yield, and catalyst recyclability. Graphical Abstract: [Figure not available: see fulltext.]
- Mei, Hui,Xiao, Se,Zhu, Tianwu,Lei, Yizhu,Li, Guangxing
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p. 443 - 450
(2014/05/20)
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- Ligand-free palladium-catalyzed aerobic oxidative coupling of carboxylic anhydrides with arylboronic acids
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We report a new, effective and environmentally friendly protocol for selective aerobic oxidative coupling of arylboronic acids with carboxylic anhydrides in the presence of ligand-free palladium catalyst. The aryl benzoates are obtained in good to excellent yields.
- Yin, Weiyan,He, Haifeng,Zhang, Yani,Long, Tong
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p. 2402 - 2406
(2014/10/15)
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- Enthalpy-entropy correlations in reactions of aryl benzoates with potassium aryloxides in dimethylformamide
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Temperature dependences of the relative reactivity of potassium aryloxides XC6H4O-K+ toward 4-nitrophenyl (1), 3-nitrophenyl (2), 4-chlorophenyl (3), and phenyl (4) benzoates in dimethylformamide (DMF) were studied using the competitive reactions technique. The rate constants kX for the reactions of 1 with potassium 4-cyanophenoxide, 2 with potassium 3-bromophenoxide, 3 with potassium 3-bromo-, 4-bromo-, and unsubstituted phenoxides, 4 with potassium 4-methoxy- and 3-methylphenoxides were measured at 25°C. Correlation analysis of the relative rate constants kX/kH(3-Me) and differences in the activation parameters (δδH≠and δ δS ≠) of competitive reactions revealed the existence of six isokinetic series. We investigated the substituent effect of X on the activation parameters for each isokinetic series and concluded that the reactions of aryl benzoates PhCO2C6H4Y with potassium aryloxides in DMF proceed via a four-step mechanism. The large ρ0(Y) and ρXY values at 25°C obtained for the reactions of 1-3 with potassium aryloxides with an electron-donating substituent refer to the rate-determining formation of the spiro-σ-complex. The Hammett plots for the reactions of 1 and 2 exhibit a downward curvature, causing the motion of the transition state for the rate-determining step according to a Hammond effect as the substituent in aryloxide changes from electron-donating to electron-withdrawing. Analysis of data in the terms of two-dimensional reaction coordinate diagrams leads to the conclusion that significant anti-Hammond effects arise in the cases of ortho-substituted and unsubstituted substrates. It was shown that the isokinetic and compensation effects observed for the reactions of aryl benzoates with potassium aryloxides in DMF can be interpreted in the terms of the electrostatic bonding between the reaction centers.
- Khalfina, Irina A.,Vlasov, Vladislav M.
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p. 266 - 282
(2013/05/21)
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- Palladacycle-catalyzed carbonylation of aryl iodides or bromides with aryl formates
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An efficient palladacycle-catalyzed aromatic carbonylation reaction of aryl formates with aryl iodides or bromides has been developed. Commercially available and easily prepared aryl formates were employed as carbonyl sources without the use of external carbon monoxide. The present catalytic system shows broad functional group tolerance and affords aryl benzoate derivatives in good to excellent yields. Copyright
- Chen, Guangwei,Leng, Yuting,Yang, Fan,Wang, Shiwei,Wu, Yangjie
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p. 1488 - 1494
(2014/01/06)
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- Immobilized palladium metal-containing ionic liquid-catalyzed alkoxycarbonylation, phenoxycarbonylation, and aminocarbonylation reactions
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Immobilized palladium metal-containing ionic liquid (ImmPd-IL), a structurally well-defined transition metal complex, is explored as an immobilized, phosphine-free catalyst for carbonylation reactions, including alkoxycarbonylation, phenoxycarbonylation, and aminocarbonylation reactions. The effect of various reaction parameters, such as solvent, base, time, temperature, and CO pressure on carbonylation reactions using ImmPd-IL catalyst was investigated. The optimized protocol was applied to a wide variety of substituted aryl iodides and various alcohol/phenols and amines having different steric and electronic properties and afforded the corresponding products in good to excellent yield. The developed catalytic system circumvents the use of phosphine ligands, with an additional advantage of palladium catalyst recovery and reuse for up to four consecutive cycles. The recycled catalyst was characterized using XPS analysis.
- Khedkar, Mayur V.,Sasaki, Takehiko,Bhanage, Bhalchandra M.
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p. 287 - 293
(2013/08/25)
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- Palladium-catalyzed esterification of aryl halides using aryl formates without the use of external carbon monoxide
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Aryl formates are efficient carbon monoxide sources in palladium-catalyzed esterification of aryl halides. The carbonylation readily proceeds at ambient pressure without the use of external carbon monoxide to afford the corresponding esters in high yields.
- Fujihara, Tetsuaki,Hosoki, Tomoya,Katafuchi, Yuko,Iwai, Tomohiro,Terao, Jun,Tsuji, Yasushi
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p. 8012 - 8014
(2012/09/08)
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- Trichlorophenyl formate: Highly reactive and easily accessible crystalline CO surrogate for palladium-catalyzed carbonylation of aryl/alkenyl halides and triflates
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The high utility of 2,4,6-trichlorophenyl formate, a highly reactive and easily accessible crystalline CO surrogate, is demonstrated. The decarbonylation with NEt3 to generate CO proceeded rapidly at rt, thereby allowing external-CO-free Pd-catalyzed carbonylation of aryl/alkenyl halides and triflates. The high reactivity of the CO surrogate enabled carbonylation at rt and significantly reduced the quantities of formate to near-stoichiometric levels. The obtained trichlorophenyl esters can be readily converted to a variety of carboxylic acid derivatives in high yields.
- Ueda, Tsuyoshi,Konishi, Hideyuki,Manabe, Kei
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p. 5370 - 5373,4
(2012/12/12)
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- Ruthenium/NHC-catalyzed tandem benzylic oxidation/oxidative esterification of benzylic alcohols with phenols
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An efficient methodology to access benzoate derivatives via tandem benzylic oxidation/oxidative esterification of benzylic alcohols with phenols catalyzed by ruthenium/NHC was developed. This operationally simple one-pot process uses O2 as the clean oxidant, producing esters in good to excellent yields.
- Zhang, Di,Pan, Changduo
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experimental part
p. 41 - 45
(2012/06/18)
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- An efficient synthesis of thioesters via TFA-catalyzed reaction of carboxylic acid and thiols: Remarkably facile C-S bond formation
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A general, facile, and efficient new synthetic path to thioesters was established by employing defined TFA-catalyzed reaction of carboxylic acid and thiol under mild conditions. The structure of the newly synthesized compounds was determined by infrared spectroscopy, nuclear magnetic resonance, and a single crystal X-ray crystallographic analysis. Supplemental materials are available for this paper. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. Copyright
- El-Azab, Adel S.,Abdel-Aziz, Alaa A.-M.
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experimental part
p. 1046 - 1055
(2012/07/17)
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- Green and efficient method for the acylation of amines and phenols in the presence of hydrotalcite in water
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In this study a mild, efficient and environmentally friendly method has been developed for the synthesis of amides and esters in the presence of hydrotalcite in water at room temperature. Different types of amines and phenols have been used and in all cases the products were obtained in moderate to high yields after an easy work-up. This method follows the principles of green chemistry.
- Massah, Ahmad Reza,Toghyani, Mitra,Najafabadi, Batool Hojati
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p. 603 - 605,3
(2020/09/16)
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- Palladium-catalyzed aerobic oxidative coupling of acyl chlorides with arylboronic acids
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The first example of a palladium-catalyzed aerobic oxidative coupling of acyl chlorides with arylboronic acids has been developed, leading to a wide range of aryl benzoates in good to excellent yields. This catalytic system shows broad functional group tolerance. Preliminary mechanistic experiments using deuterium labeling showed that the oxygen atom was derived from dioxygen. Copyright
- Chen, Jiuxi,Peng, Yong,Liu, Miaochang,Ding, Jinchang,Su, Weike,Wu, Huayue
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supporting information
p. 2117 - 2122
(2012/11/07)
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- Rhodium-catalyzed acyl-transfer reaction between benzyl ketones and thioesters: Synthesis of unsymmetric ketones by ketone CO-C bond cleavage and intermolecular rearrangement
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In the presence of catalytic amounts of RhH(CO)(PPh3) 3 and 1,2-bis(diphenylphosphino)benzene (dppBz), acyl groups were transferred between benzyl ketones and thioesters/aryl esters. The rhodium complex catalyzed the cleavage of keto
- Arisawa, Mieko,Kuwajima, Manabu,Toriyama, Fumihiko,Li, Guangzhe,Yamaguchi, Masahiko
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supporting information; experimental part
p. 3804 - 3807
(2012/09/07)
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- Palladium/NHC-catalyzed tandem benzylic oxidation/oxidative esterification of benzylic alcohols with phenols
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A palladium/NHC-catalyzed tandem benzylic oxidation/oxidative esterification of benzylic alcohols with phenols to access aryl benzoate derivatives is described. The procedure tolerates a series of functional groups, such as methoxy, nitro, cyano, chloro, fluoro and bromo groups. Thus, it represents a practically alternative method to access aryl benzoate derivatives.
- Luo, Fang,Pan, Changduo,Cheng, Jiang,Chen, Fan
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supporting information; experimental part
p. 5878 - 5882
(2011/09/12)
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- Fe-catalyzed thioesterification of carboxylic esters
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Second nature: Starting from shelf-stable aryl esters and thiols, a variety of carboxylic acid esters were transformed into the corresponding thioesters with no racemization of labile stereocenters (see scheme). The method was successfully applied in a native chemical-ligation-type peptide formation, which suggests that the thiol may act as a co-catalyst for future 1,2-additions of pronucleophiles to carboxylic esters.
- Magens, Silja,Plietker, Bernd
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supporting information; experimental part
p. 8807 - 8809
(2011/09/16)
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- Iron-doped single-walled carbon nanotubes as new heterogeneous and highly efficient catalyst for acylation of alcohols, phenols, carboxylic acids and amines under solvent-free conditions
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Iron-doped single-walled carbon nanotubes (Fe/SWCNTs) represent an efficient and new heterogeneous reusable catalyst for the acylation of a variety of alcohols, phenols, carboxylic acids and amines with acid chlorides or acid anhydrides under solvent-free conditions. The reactions of various primary, secondary, tertiary, and benzylic alcohols, diols, phenols, as well as aromatic and aliphatic amines give acylated adducts in good to excellent yields.
- Sharghi, Hashem,Jokar, Mahboubeh,Doroodmand, Mohammad Mahdi
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experimental part
p. 426 - 442
(2011/04/15)
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- Enthalpy-entropy correlations in reactions of 2,4-dinitrophenyl benzoate with phenols in the presence of potassium hydrogen carbonate and with potassium phenoxides in dimethylformamide
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Temperature dependences of the relative reactivity of substituted phenols RC6H4OH in the presence of potassium hydrogen carbonate and of potassium phenoxides RC6H4O-K + toward 2,4-dinitrophenyl benzoate in dimethylformamide were studied using the competitive reactions technique. Correlation analysis of the relative rate constants kR/kH and differences in the activation parameters (ΔΔH{double barred pipe} and ΔΔS{double barred pipe}) of competitive reactions revealed the existence of two isokinetic series for each type of nucleophiles. The mechanism of transesterification was interpreted in terms of an approach based on analysis of the effect of substituent in the nucleophile on the activation parameters. Pleiades Publishing, Ltd., 2011.
- Khalfina,Vlasov
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experimental part
p. 845 - 854
(2011/10/19)
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- Palladium/NHC-catalyzed oxidative esterification of aldehydes with phenols
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A palladium-catalyzed oxidative esterification of aldehydes with phenols is described, using air as the clean oxidant. This reaction tolerates many functional groups, providing esters with yields ranging from moderate to excellent.
- Zhang, Manli,Zhang, Shouhui,Zhang, Guoying,Chen, Fan,Cheng, Jiang
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experimental part
p. 2480 - 2483
(2011/05/16)
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- NHC/Iron cooperative catalysis: Aerobic oxidative esterification of aldehydes with phenols
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An NHC/iron cooperative catalytic system mediates the aerobic oxidative esterification of aldehydes with phenols. The use of equimolar amounts of reactants led to good to excellent isolated yields of esters.
- Reddy, R. Sudarshan,Rosa, Joao N.,Veiros, Luis F.,Caddick, Stephen,Gois, Pedro M. P.
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supporting information; experimental part
p. 3126 - 3129
(2011/05/12)
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- Nucleophilic iron catalysis in transesterifications: Scope and limitations
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Figure presented The ester bond is one of the most common structural motifs found in nature. Apart from the condensation between an acid and an alcohol, transesterifications represent another mechanistic alternative for the preparation of this compound class. The present paper summarizes our most recent investigations in this field, using nucleophilic iron complexes as catalysts for transesterifications under neutral conditions. This new type of metal catalyst complements the existing methodologies, which rely on Lewis acidic metal complexes. Investigations on scope and limitations, stereochemical course, and chemoselectivities will be presented.
- Magens, Silja,Plietker, Bernd
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supporting information; experimental part
p. 3715 - 3721
(2010/08/07)
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