- One-pot synthesis of ω-chloroesters via the reaction of acid chlorides with tetrahydrofuran in the presence of trichloroborane
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The reaction of acid chlorides with tetrahydrofuran in the presence of trichloroborane produces ω-chloroesters in excellent yields.
- Malladi, Rama R.,Kabalka, George W.
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Read Online
- Synthesis of chloroesters by the reaction of ethers with acyl chlorides catalyzed by ZnO
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An efficient method for the synthesis of chloroesters by the reaction of ethers with acyl chlorides catalyzed by nano-ZnO under solvent-free condition at room temperature was described. The method is compatible with a range of ethers including tricyclic ethers, tetracyclic ethers, pentacyclic ethers and hexacyclic ethers and have afforded the products with moderate to good yields. The ZnO could be reused up to three times and the product yield after three cycles is 87%.
- Tang, Yuqi,Feng, Chengliang,Yang, Wanfeng,Ji, Min,Wang, Wei,Chen, Junqing
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- Synthesis, in silico study and antimicrobial activity of new piperine derivatives containing substituted δ-esters
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A series of fifteen new piperine-derived diesters was synthesized through the substitution reaction between the salt of piperic acid, obtained through piperine basic hydrolysis, with the δ-chloro-esters, obtained through the cleavage of tetrahydrofuran (THF) with acyl chlorides in the presence of ZnCl2. The final compounds were obtained with yields ranging from 50 to 84% and were characterized by infrared (IR) and 1H and 13C nuclear magnetic resonance spectroscopy (NMR). The new compounds were evaluated in silico in regard to their ADME (absorption, distribution, metabolism, and excretion) properties, and in vitro for their antimicrobial activity against bacteria strains (Staphylococcus aureus and Pseudomonas aeruginosas), yeast fungi (Candida albicans and C. tropicalis) and filamentous fungi (Aspergillus fumigatus, A. flavus and A. niger). The results from the in silico studies of Lipinski's rule of five showed that most compounds present good pharmacological possibilities, and the results from in vitro antimicrobial activity showed that 8 of the 15 synthesized compounds displayed antimicrobial activity, inhibiting the growth of 40-80% of tested strains, with a minimum inhibitory concentration (MIC) interval ranging from 1024 to 256 μg mL-1
- Barbosa-Filho, José M.,Brandao, Maria C. R.,De Athayde-Filho, Petr?nio F.,Dutra, Thalisson F.,Lima, Edeltrudes O.,Lira, Bruno F.,Neto, Hermes Diniz,Trindade, Emmely O.
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p. 2590 - 2602
(2020/11/18)
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- Preparation method of p-phenylbutoxybenzoic acid
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The invention discloses a preparation method of p-phenylbutoxybenzoic acid. The preparation method comprises the following steps: using tetrahydrofuran as an initial raw material; carrying out a catalytic reaction with benzoyl chloride to prepare 4-chlorobutanol benzoate; carrying out a Friedel-Crafts alkylation reaction and hydrolysis on 4-chlorobutanol benzoate and benzene to obtain 4-phenylbutanol, carrying out a reaction on the 4-phenylbutanol and thionyl chloride to obtain 4-phenylchlorobutane, carrying out an alkylation reaction on the 4-phenylchlorobutane and methyl p-hydroxybenzoate under the action of potassium carbonate to obtain methyl p-phenylbutoxybenzoate. The raw materials used in the invention are cheap and easily available, the process is easy to realize industrialization,and the obtained final product has the advantages of high purity, novel route, short synthesis route, no dangerous process and simple equipment.
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Paragraph 0043-0046
(2020/07/24)
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- A Straightforward Conversion of Activated Amides and Haloalkanes into Esters under Transition-Metal-Free Cs 2 CO 3 /DMAP Conditions
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The esterification of activated amides, N -acylsaccharins, under transition-metal-free conditions with good functional group tolerance has been developed, resulting in C-N cleavage leading to efficient synthesis of a variety of esters in moderate to good yields. This work demonstrates that esterification may proceed by using simple N -acylsaccharins, haloalkanes, and Cs 2 CO 3 as oxygen source.
- Chen, Liuqing,Gu, Ying,Jian, Junsheng,Liu, Yueping,Miao, Liqiong,Wang, Zijia,Zeng, Zhuo
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supporting information
p. 4078 - 4084
(2019/10/28)
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- Synthesis and characterization of 4-chlorobutyl ester of 5-(8-carboxyl-1-naphthyl)-10,15,20-triphenyl-porphyrin and its zinc complex
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In the presence of Br?nsted–Lowry acids (phenol or dry HCl), the acyl chloride, which was obtained by the reaction between 5-(8-carboxyl-1-naphthyl)-10,15,20-triphenyl-porphyrin (CNTPP) and oxalyl chloride, reacted with tetrahydrofuran and led to the 4-chlorobutyl ester, P1, as the result of the acylative cleavage. P1 and its zinc complex [ZnP1] have been characterized by1H NMR. The structure of [ZnP1] was obtained by X-ray crystallography. Zinc is coordinated by four pyrrole nitrogens. The 8-position substituent, a 4- chlorobutyl ester group, lies above the porphyrin plane.
- Liu, Huan,Ou, Caifen,Ma, Ben,Hu, Chuanjiang
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p. 597 - 602
(2017/08/10)
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- Method for generating ester through reaction of benzoyl chloride and halogenated hydrocarbon
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The invention discloses a method for generating ester through reaction of benzoyl chloride and halogenated hydrocarbon. According to the method, benzoyl chloride, halogenated hydrocarbon and carbonate which are reaction substrates are heated and stirred to react in the presence of a catalyst 4-dimethylaminopyridine (DMAP) in an air or inert gas atmosphere to generate a corresponding ester product. The method disclosed by the invention has the beneficial effects that benzoyl chloride, halogenated hydrocarbon and carbonate are taken as the reaction substrates for the first time, carbonate is found as a source of oxygen in the product for the first time, and the reaction is found as a free radical mechanism for the first time.
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Paragraph 0021; 0022; 0023
(2017/08/31)
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- Palladium(II) acetate catalyzed acylative cleavage of cyclic and acyclic ethers under neat conditions
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During the development of a palladium catalyzed C–H activation cross-coupling reaction involving acyl halides, it was noted that palladium(II) acetate catalyzes the acylative cleavage of tetrahydrofuran (used as a solvent) at room temperature to afford the corresponding 4-chlorobutyl ester derivative. After optimization, the reaction was shown to work well with epoxides, oxetane and tetrahydrofuran, but only barely with oxanes at room temperature. Acyclic ethers systematically failed to react under similar conditions, but underwent complete conversion in a microwave reactor at 100 °C.
- Fotie, Jean,Adolph, Brandy R.,Bhatt, Shreya V.,Grimm, Casey C.
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supporting information
p. 4648 - 4651
(2017/11/15)
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- Reaction of Acyl Chlorides with in Situ Formed Zinc Selenolates: Synthesis of Selenoesters versus Ring-Opening Reaction of Tetrahydrofuran
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Attempting to apply the in situ production of PhSeZnSePh to the synthesis of selenoesters, an unexpected reaction involving the solvent (tetrahydrofuran) was observed and studied. We reported here some evidences about the mechanism and the possibility to
- Bellino, Gemma,Scisciani, Marialaura,Vargas, Jaqueline Pinto,Sancineto, Luca,Bagnoli, Luana,Marini, Francesca,Lüdtke, Diogo Seibert,Lenardao, Eder Joao,Santi, Claudio
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- An Effective Method for the Construction of Esters Using Cs2CO3 as Oxygen Source
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An effective method for the construction of esters from acyl chloride and halohydrocarbon using Cs2CO3 as an oxygen source was achieved for the first time. The methodology has a wide scope of substrates and can be scaled up. The study of a preliminary reaction mechanism demonstrated that the O in the products comes from Cs2CO3 and this esterification proceeds through a free radical reaction. It was also found that CO2 can also be used in this esterification reaction as an oxygen source.
- Ren, Lanhui,Wang, Lianyue,Lv, Ying,Li, Guosong,Gao, Shuang
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supporting information
p. 5172 - 5175
(2015/11/24)
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- An efficient iron catalyzed regioselective acylative cleavage of ethers: Scope and mechanism
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A method involving iron catalyzed acylative cleavage of cyclic and acyclic ethers with acyl/aroyl chlorides has been studied to produce chloroesters and esters respectively. Examination of the scope revealed that less electron rich alkyl group in unsymmetric, acyclic ether was acylated while the chloride derived from the counterpart moiety was volatile and difficult to isolate. In contrast, α-branched cyclic ethers were converted to the corresponding primary ester and secondary chloride. Steric hindrance of ether also plays an important role in acylative C-O bond cleavage. The mechanism of ether cleavage is proposed to involve a single electron initiated SN1 dissociative pathway.
- Bodduri, V.D. Vijaykumar,Choi, Kyung-Min,Vaidya, Raghavender Rao,Patil, Kalpesh,Chirumarry, Sridhar,Jang, Kiwan,Yoon, Yong-Jin,Falck, John R.,Shin, Dong-Soo
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supporting information
p. 7089 - 7093
(2015/12/01)
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- Heavier chalcogenone complexes of bismuth(iii)trihalides: Potential catalysts for acylative cleavage of cyclic ethers
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Heavier chalcogenones (S, Se and Te) of imidazole act as versatile ligands to yield a series of mononuclear and dinuclear bismuth(iii)complexes of heavier chalcogenones in excellent yield. These new bismuth heavier chalcogen derivatives are the first structurally characterized molecules, where the bismuth and heavier chalcogen ratio is 1:1. There is only one previous report of a crystal structure of a bismuth(iii)-imidazol selone compound and none with bismuth(iii)-imidazol tellone. The bismuth center in monomeric bismuth chalcogen trihalides depicts pseudo trigonal bipyramidal geometry, while the dimeric bismuth chalcogen trihalides demonstrate distorted square pyramidal geometry. The solid state structures of bismuth chalcogenone derivatives feature rare Bi...π(aryl) interactions. Thus, the centroid of the C6-ring suggests a half sandwich type of bismuth environment in mononuclear and dinuclear bismuth(iii) chalcogenone complexes. Notably, the Bi...π(aryl) interaction is not often noticed for mononuclear bismuth chalcogen compounds. Some of the bismuth(iii) chalcogenone complexes also exhibit C-H...π(aryl), C-H...S and C-H...Cl types of hydrogen bonding. The bismuth-chalcogen bond distance in mononuclear bismuth(iii)tribromide chalcogenone complexes is slightly longer than in mononuclear bismuth(iii)trichloride chalcogenone complexes. A gradual increase in carbon-chalcogen bond distance was observed from the free imidazole-chalcogenone to mononuclear bismuth(iii)trichloride chalcogenones, dinuclear bismuth(iii)trichloride chalcogenones and mononuclear bismuth(iii)tribromide chalcogenones and dinuclear bismuth(iii)tribromide chalcogenones. The UV-vis absorption properties and thermal decomposition properties of imidazol chalcogenones and their bismuth derivatives were investigated. Furthermore, the O-acylative cleavage of cyclic ethers was demonstrated using mononuclear and dinuclear bismuth(iii)complexes of heavier chalcogenones as catalysts. In contrast to bismuth(iii)trichloride and bismuth(iii)tribromide catalysts, mononuclear and dinuclear bismuth(iii)complexes of heavier chalcogenones are very active towards an acylative cleavage of cyclic ethers through a mild and regioselective strategy. In particular, mononuclear imidazolthione-bismuth(iii)trichloride is very active towards O-acylative cleavage of 2-methyl tetrahydrofuran. This journal is
- Srinivas, Katam,Suresh, Paladugu,Babu, Chatla Naga,Sathyanarayana, Arruri,Prabusankar, Ganesan
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p. 15579 - 15590
(2015/03/05)
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- Copper-catalyzed Csp3-O cross-coupling of unactivated alkyl halides with organic peroxides
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An efficient Cu-catalyzed Csp3-O coupling of peroxides with haloalkanes is described. High yields of products were achieved under mild conditions. Significantly, in addition to primary alkyl halides, secondary alkyl halogenated hydrocarbons could also be applied to this system. The new reaction system could tolerate a wide range of organic peroxides.
- Chen, Huan-Huan,Wang, Guang-Zu,Han, Jin,Xu, Meng-Yu,Zhao, Yong-Qiang,Xu, Hua-Jian
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p. 212 - 217
(2014/01/06)
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- Palladium-catalyzed and copper-mediated cross-coupling reaction of aryl- or alkenylboronic acids with acid chlorides under neutral conditions: Efficient synthetic methods for diaryl ketones and chalcones at room temperature
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Palladium-catalyzed cross-coupling reaction of aryl- or alkenylboronic acids with acid chlorides in the presence of copper(I) thiophene-2-carboxylate (CuTC) as an activator in diethyl ether at room temperature under strictly non-basic conditions affords the diaryl ketones or chalcones in moderate to excellent yields. A wide range of substrates bearing an electron-donating or an electron-withdrawing substituent on the aromatic ring are compatible.
- Ogawa, Daisuke,Hyodo, Keita,Suetsugu, Masato,Li, Jing,Inoue, Yoshiaki,Fujisawa, Mamoru,Iwasaki, Masayuki,Takagi, Kentaro,Nishihara, Yasushi
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p. 2565 - 2571
(2013/03/28)
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- Synthesis of δ- And ε-cyanoesters by zinc-catalyzed ring-opening of cyclic ethers with acid chlorides and subsequent cyanation
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In the present study, the zinc-catalyzed cleavage of cyclic ethers with acid halides as nucleophiles to yield chloroesters with different chain length has been investigated in detail. In the presence of straightforward and commercially available zinc salts as pre-catalysts excellent yields and selectivities were feasible. After studying the reaction conditions and the scope of the method, several efforts were carried out to understand the reaction mechanism. The obtained chloroesters were subsequently converted to δ- and ε-cyano esters, which are useful precursors in natural product synthesis. Graphical Abstract: [Figure not available: see fulltext.]
- Enthaler, Stephan,Weidauer, Maik
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experimental part
p. 168 - 175
(2012/03/27)
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- Orthoamides and iminium salts LXXIV [1]. Reactions of N,N,N',N'- Tetramethyl-chloroformamidiniumChloride with metals
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N,N,N',N'-Tetramethyl-formamidinium chloride (2a) reacts with elemental sodium in various solvents to give N,N,N',N',N'',N''-hexamethyl-guanidinium chloride (4a). The reaction of 2a with potassium affords N,N,N',N',N'',N'',N''', N'''-octamethyl-oxamidinium dichloride (3a). From the reaction of 2a with magnesium in different solvents in general result mixtures of the salts 4a, 3a and N,N,N',N'-tetramethyl-formamidinium chloride (10a). The composition of these mixtures depends on the solvent and the reaction temperature. Similar results are obtained, when a zinc'copper couple is used instead of magnesium. Very likely from 2a and magnesium or zinc, respectively, organometallic intermediates 11, 12 are formed which could be trapped by aromatic aldehydes and phenylisocyanate. The salt 2a can be reductively coupled by a low-valent titanium reagent to give the oxamidinium salt 3a.
- Kantlehner, Willi,Aichholz, Reiner,Karl, Martin
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experimental part
p. 305 - 319
(2012/07/13)
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- Single-pot conversion of an acid to the corresponding 4-chlorobutyl ester
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A single pot conversion of carboxylic acids into the corresponding 4-chlorobutyl esters has been achieved by a novel procedure. The intermediate acid chlorides are not isolated. The double bond and aromatic methoxy group survive the mild reaction conditions. In almost all the examples studied the products are purified by simple flash chromatography.
- Pal, Sutanuka,Pal, Sudhir Chandra
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p. 596 - 599
(2012/04/18)
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- Rhenium complex-catalyzed acylative cleavage of ethers with acyl chlorides
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It was found that rhenium complex was an efficient catalyst for the acylative cleavage of C-O bond of ethers with acyl chlorides. When acyclic ethers were allowed to react with acyl chlorides in the presence of a catalytic amount of ReBr(CO)5, acylative cleavage of C-O bond of acyclic ethers smoothly proceeded to give the corresponding esters in moderate to good yields. Similarly, cyclic ethers were acylative cleaved by acyl chlorides to give the corresponding chloro substituted esters in good yields by the use of Re 2O7 catalyst.
- Umeda, Rui,Nishimura, Takashi,Kaiba, Kenta,Tanaka, Toshimasa,Takahashi, Yuuki,Nishiyama, Yutaka
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scheme or table
p. 7217 - 7221
(2011/10/08)
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- Use of magnesium (turnings) as a powerful catalyst for the o-acylative cleavage of tetrahydrofuran
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In a short reaction time, acyl chlorides and dry tetrahydrofuran react in the presence of a catalytic amount of magnesium turnings (Mg) at 25 °C to give 4-chlorobutyl esters in excellent yields. Copyright
- Pasha,Manjula, Krishnappa
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experimental part
p. 2309 - 2314
(2011/06/27)
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- Synthesis of chloroesters by the cleavage of cyclic and acyclic ethers using La(NO3)3·6H2O as a mild and efficient catalyst under solvent-free conditions
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A mild and an efficient synthesis of chloroesters is described by the reaction of cyclic and acyclic ethers with acid chlorides in the presence of a catalytic amount of La(NO3)3·6H2O under solvent-free conditions, affording the corresponding chloroesters in excellent yields. Copyright Taylor & Francis Group, LLC.
- Suresh,Suryakiran,Rajesh,Selvam, J. Jon Paul,Srinivasulu,Venkateswarlu
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- A mild and efficient synthesis of chloroesters by the cleavage of cyclic and acyclic ethers using Bi(NO3)3·5H2O as a catalyst under solvent-free conditions
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A facile, efficient synthesis of chloroesters is described. The reaction of cyclic and acyclic ethers with acid chlorides in the presence of catalytic amounts of Bi(NO3)2·5H2O under solvent-free conditions yielded the corresponding chloroesters. Also, the catalyst can be recovered conveniently and reused efficiently for at least six times.
- Suresh,Suryakiran,Venkateswarlu
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p. 1037 - 1040
(2008/09/16)
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- Simple and efficient method for the synthesis of δ-chloroesters from tetrahydrofuran and acyl chlorides in the presence of catalytic iodine
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Acyl chlorides and dry tetrahydrofuran (THF) in the presence of catalytic amounts of iodine at 25°C give δ-chloroesters in excellent yields. Copyright Taylor & Francis Group, LLC.
- Pasha,Manjula
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p. 927 - 932
(2007/10/03)
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- Bi(III) halides as efficient catalysts for the O-acylative cleavage of tetrahydrofurans: An expeditious entry to tetralins
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The mild (DCM/20°C), quantitative, regioselective, O-acylative cleavage of tetrahydrofurans using organic acid halides with catalytic Bi(III) halides is reported. X-ray crystallography is used to rationalise the failure of the reaction in the case of certain crowded acid chlorides, and a useful aspect of chemoselectivity is revealed. The synthetic potential of this reaction is illustrated with a highly efficient O-acylative cleavage/intramolecular alkylation approach to tetralins.
- Coles, Simon J.,Costello, James F.,Draffin, William N.,Hursthouse, Michael B.,Paver, Simon P.
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p. 4447 - 4452
(2007/10/03)
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- Room-temperature palladium-catalyzed and copper(I)-mediated coupling reactions of acid chlorides with boronic acids under neutral conditions
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The palladium-catalyzed cross-coupling reactions of acid chlorides with arylboronic acids in the presence of copper(I) thiophene-2-carboxylate (CuTC) as an activator under strictly non-basic and mild reaction conditions afford the unsymmetrical ketones in moderate to excellent yields. A wide range of substrates bearing an electron-donating or an electron-withdrawing substituent on the aromatic ring is compatible. Georg Thieme Verlag Stuttgart.
- Nishihara, Yasushi,Inoue, Yoshiaki,Fujisawa, Mamoru,Takagi, Kentaro
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p. 2309 - 2312
(2007/10/03)
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- Mild and efficient method for the cleavage of cyclic and acyclic ethers by iodine under solvent-free conditions
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Ethers undergo smooth cleavage with acyl chlorides in the presence of a catalytic amount of elemental iodine under extremely mild conditions to give the corresponding halo esters. This new procedure offers significant advantages such as high conversions, short reaction times and enhanced selectivity together with mild reaction conditions, which makes it an attractive strategy.
- Yadav,Reddy,Reddy, P. Murali Krishna,Gupta, Manoj K.
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p. 8493 - 8495
(2007/10/03)
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- Group 5 and group 6 metal halides as very efficient catalysts for acylative cleavage of ethers
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Group 5 and 6 metal chlorides such as MoCl5, WCl6, NbCl5 and TaCl5 were found as very efficient catalysts for acylative cleavage of the C-O bond of ethers. Compared with conventional Lewis acid catalysts such as ZnCl2, AlCl3, SnCl4 and TiCl4, group 5 and 6 metal chlorides showed better results in the catalytic C-O bond cleavage of dibutyl ether with benzoyl chloride.
- Guo, Qiaoxia,Miyaji, Taichi,Hara, Ryuichiro,Shen, Baojian,Takahashi, Tamotsu
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p. 7327 - 7334
(2007/10/03)
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- Organomercury/aluminum-mediated acylative cleavage of cyclic ethers
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Epoxides and tetrahydrofurans are cleaved with concomitant acylation to chloroalkyl esters using a reagent system composed of an organomercurial, aluminum metal and an acid chloride. The cleavage is promoted under mild conditions by a range of readily-available cyclic β-alkoxychloromercurials and acid chlorides. Using mainly tetrahydrofuran and cyclohexene oxide as substrates, the yield of isolated chloroesters ranged from 52 to 96%.
- Luzzio, Frederick A.,Bobb, Rhiana A.
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p. 1851 - 1858
(2007/10/03)
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- Preparation of 1,3-diketones by the reaction of bis(iodozincio)methene with acyl cyanides or palladium-catalyzed reaction with acyl chlorides
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Bis(iodozincio)methane, prepared from lead-catalyzed reaction of zinc with diiodomethane, afforded 1,3-diketones either by the reaction with acyl cyanides or by palladium catalyzed reaction with acyl chlorides. Reaction with adipoyl dichloride gave cyclic enol ester by intramolecular reaction.
- Matsubara, Seijiro,Kawamoto, Kazunari,Utimoto, Kiitiro
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p. 267 - 268
(2007/10/03)
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- Studies on organolanthanide complexes XXXVII. Reaction of dicyclopentadienylyttrium chloride with acyl chlorides in tetrahydrofuran. Acylative cleavage of the Cp-Y ?-bond and tetrahydrofuran ring
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Dicyclopentadienylyttrium chloride reacts with aromatic and aliphatic acid chlorides in tetrahydrofuran at room temperature, resulting in cleavage of the Cp-Y ?-bond to produce 1,5-diacylcyclopentadienes, and the acylative ring-opening of tetrahydrofuran.A possible reaction mechanism is proposed.
- Qian, Changtao,Qiu, Aineng,Huang, Yaozeng,Chen, Wenjie
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- Cobalt(II)chloride catalysed cleavage of ethers with acyl halides: Scope and mechanism
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Cobalt(II) chloride in acetonitrile catalyses the cleavage of a wide variety of ethers with acyl halides under mild conditions to give the corresponding esters in good yields. Acyclic aliphatic ethers are cleaved to the corresponding ester and chlorides whereas the cyclic aliphatic ethers give rise to the ω-chloroesters. The benzyl ethers can be converted to the corresponding esters along with the formation of benzyl chloride and benzyl acetamide. A comparative study for the cleavage of allyl and benzyl ether has revealed that benzyl ether can be selectively cleaved in presence of the allyl ethers. The oxiranes can be cleaved in highly regioselective manner to the corresponding-β-chloroesters. The vinyl ethers undergo sp2-hybridised carbon-oxygen bond cleavage under these conditions. Based on product analysis, a mechanism involving electron transfer followed by O-acylation and S(N)1 or S(N)2 attack by chloride-ion is discussed.
- Iqbal,Srivastava
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p. 3155 - 3170
(2007/10/02)
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- Non-Catalyzed Cleavage Reactions of Ethers with Acyl Halides under High-Pressure Conditions
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Various cyclic and acyclic ethers are efficiently cleaved with acyl chlorides or bromides to give ω-chloro- or ω-bromoesters under high-pressure conditions.
- Kotsuki, Hiyoshizo,Ichikawa, Yoshikatsu,Nishizawa, Hitoshi
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p. 673 - 676
(2007/10/02)
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- Cobalt(II) Chloride Catalysed Acylative Cleavage of Ethers
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In the presence of catalytic amount of cobalt(II) chloride in acetonitrile, a wide variety of ethers are cleaved with acyl chlorides, to the corresponding esters in good to excellent yield.
- Ahmad, Saeed,Iqbal, Javed
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p. 953 - 956
(2007/10/02)
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- Studies on the Occurence of Hydrogen Transfer, 67. Enediol Diesters by Acylating Electroreductive Dimerization of Acyl Chlorides with Lithium Amalgam
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Aromatic, aliphatic, and aromatic-aliphatic acyl chlorides (and anhydrides) are transformed by lithium amalgam (Li/Hg) to cis- and/or trans enediol diesters 1-10 (acylating reductive dimerization), mostly in ca. 70percent yields.The influence of the solvent on the reaction course is investigated.Starting from 2,2'-biphenyldicarbonyl dichloride, the phenanthrene 7 is formed; phthalide 8 is the reaction-product using phthaloyl dichloride as starting material.Diphenylphosphinyl chloride is reduced by Li/Hg to tetraphenyldiphosphane dioxide (15).A reaction mechanism for the acylating reductive dimerization is proposed on the basis of the halve-wave potentials determined for 12 acyl chlorides and four 1,2-diketones.The latter are intermediates in the acylating reductive dimerization of the acyl chlorides.Enediol diesters are obtained starting from 1,2-diketones and Li/Hg in the presence of acyl chlorides.Trimethylsilyl chloride is unsuitable as a trap for the enediols; it is preferentially reduced at the Li/Hg interface.Tetrahydrofuran as solvent is transformed to RC(O)O-4-Cl by a known ring-opening acylation reaction in the presence of Lewis acids (LiCl or ZnCl2) formed by the decomposition of Li/Hg and Zn/Hg.
- Horner, Leopold,Dickerhof, Karlheinz
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p. 1603 - 1614
(2007/10/02)
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- THE TITANOCENE METHYLENE-ZINC HALIDE COMPLEX: A CONVENIENT SYNTHESIS AND ITS METHYLENATING ACTION ON UNSATURATED CARBON CENTERS
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The titanocene methylene-zinc halide complex, which can be conveniently prepared by treating titanocene dichloride with methylenezinc iodide in THF solution, readily methylenates ketones, nitriles, and alkynes.
- Eisch, John J.,Piotrowski, Andrzej
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p. 2043 - 2046
(2007/10/02)
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- Acylative Cleavage of Ethers Catalyzed by Triorganotin Halides and Palladium(II) Complexes
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Benzylic, allylic, and cyclic ethers react with acyl halides under mild conditions in the presence of triorganotin halide and palladium(II) catalysts to give the corresponding esters in good yields.In the case of benzyl ether the other product is the benzyl halide, while in the reaction of allylic ethers the other products are various olefins resulting from the cleavage of the allyl group and an organotin moiety.The reaction is selective to these ethers, while acyclic aliphatic and phenolic ethers are unreactive.By control of the reaction conditions, benzylic andcyclic ethers could be cleaved in the presence of allylic ethers.The utility of the reaction as a deprotective method is demonstrated by the cleavage of a benzylic ether containing olefinic unsaturation.The mechanism of the benzylic and allylic ethers cleavage was studied by carrying out the corresponding stoichiometric reactions with the various palladium(II) complexes proposed in the catalytic cycle.
- Pri-Bar, I.,Stille, J. K.
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p. 1215 - 1220
(2007/10/02)
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