- INTERMEDIATES IN THE LEUCKART REACTION OF BENZOPHENONE WITH FORMAMIDE
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The isolation of benzhydrol and its ether in conjunction with N-formylbenzhydrylamine in the Leuckart reaction of benzophenone is reported; it is postulated that this alcohol is a possible intermediate in the reaction.
- Agwada, Vincent C.,Awachie, Peter I.
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- Room temperature reactions of XeF2 with phenyl substituted alcohols
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Benzyl alkohol and its analogues with a non-activated benzene ring are transformed to fluoromethoxy derivatives by reaction with XeF2. The same reaction with diphenyl methanol gives di diphenylmethylether, while 2-phenyl-2-propanol transforms to 2,4-diphenyl-4-methyl-1-pentene.
- Stavber, Stojan,Zupan, Marko
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- An expedient, efficient and solvent-free synthesis of T3P-mediated amidation of benzhydrols with poorly reactive N-nucleophiles under MW irradiation
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An expedient, efficient, economical, environmentally benign, and solvent free amidation protocol of benzhydrols with less reactive nitrogen nucleophiles assisted by propylphosphonic anhydride (T3P) under microwave irradiation has been developed. The methodology has been deployed for a wide range of heterocycles and electron-withdrawing & electron-donating groups. The protocol resulted in good to excellent yields under the given conditions (26 examples, 68-93% yield).
- Cheruku, Srinivas,Manikyanally, Kumara N.,Mantelingu, Kempegowda,Nagarakere, Sandhya C.,Narayana, Yatheesh,Rangappa, Kanchugarakoppal S.,Sunilkumar, Makanahalli P.
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p. 4421 - 4426
(2022/03/14)
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- Synthetic method of borane-catalyzed symmetric ether
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The invention provides a borane-catalyzed symmetric ether synthesis method, which is characterized in that alcohol is used as a raw material, and under the catalysis of B(2,6-Cl2C6H3) (p-HC6F4) 2, etherification reaction is carried out through intermolecular dehydration to generate ether. The reaction process is simple, mild, pollution-free and efficient.
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Paragraph 0073-0082
(2021/07/28)
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- Monoallylation and benzylation of dicarbonyl compounds with alcohols catalysed by a cationic cobalt(iii) compound
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Monoallylation and monoalkylation of diketones and β-keto esters with allylic and benzylic alcohols catalysed by [Cp*Co(CH3CN)3][SbF6]2(I) are reported. The method does not require any additive and affords regioselective products. The mechanistic investigations were done byin situ1H NMR spectroscopy as well as control experiments. It has been shown that reactions proceedviaη3-allyl complex formation or ally ether intermediate. The alkylation takes placeviaonly ether intermediate. The resulting allylated and alkylated products have been used for the synthesis of eleven new trisubstituted pyrazoles and one pyrazolone.
- Chandra Sau, Mohan,Mandal, Smita,Bhattacharjee, Manish
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p. 9235 - 9245
(2021/03/16)
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- Deoxygenation of tertiary and secondary alcohols with sodium borohydride, trimethylsilyl chloride, and potassium iodide in acetonitrile
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The deoxygenation of tertiary and secondary alcohols to give the corresponding alkanes is conventionally performed using an organosilane and a strong acid. In this study, a deoxygenation method was developed for tertiary and secondary alcohols, using trimethylsilane and trimethylsilyl iodide generated in situ from sodium borohydride and trimethylsilyl chloride, and trimethylsilyl chloride and potassium iodide, respectively. With our method, tertiary and secondary alcohols, which provided stable carbocations, were converted into the corresponding alkanes. This paper also presents the optimization of the reaction conditions, the reaction mechanism, as well as the scope and limitations of the method.
- Kato, Yuichi,Inoue, Tomoka,Furuyama, Yuuki,Ohgane, Kenji,Sadaie, Mahito,Kuramochi, Kouji
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supporting information
(2021/11/16)
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- Mechanochemical Nucleophilic Substitution of Alcohols via Isouronium Intermediates**
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An expansion of the solvent-free synthetic toolbox is essential for advances in the sustainable chemical industry. Mechanochemical reactions offer a superior safety profile and reduced amount of waste compared to conventional solvent-based synthesis. Here
- Aav, Riina,Dalidovich, Tatsiana,Kananovich, Dzmitry G.,Nallaparaju, Jagadeesh Varma,Shalima, Tatsiana
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- Microwave-Assisted Condensation of Benzylic Alcohols and Alkynes Promoted by Zinc Halides: Concise Access to Alkenyl Halides
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A simple Lewis acid-mediated route for the synthesis of alkenyl halides are described under microwave-assisted conditions. The reaction proceeds through the condensation between secondary alcohols and terminal acetylenes and regioselective hydrohalogenati
- Goel, Komal,Nandi, Poulomi,Satyanarayana, Gedu,Sreenivasulu, Chinnabattigalla
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p. 4851 - 4860
(2021/11/17)
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- Photoelimination of Nitrogen from Diazoalkanes: Involvement of Higher Excited Singlet States in the Carbene Formation
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Although diazoalkanes are important carbene precursors in organic synthesis, a comprehensive mechanism of photochemical formation of carbenes from diazoalkanes has not been proposed. Synergies of experiments and computations demonstrate the involvement of higher excited singlet states in the photochemistry of diazoalkanes. In all investigated diazoalkanes, excitation to S1 results in nonreactive internal conversion to S0. On the contrary, excitation to higher-lying singlet states (Sn, n > 1) drives the reaction toward a different segment of the S1/S0 conical intersection seam and results in nitrogen elimination and formation of carbenes.
- Pite?a, Tomislav,Ale?kovi?, Marija,Becker, Kristin,Basari?, Nikola,Do?li?, Nada
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p. 9718 - 9724
(2020/07/02)
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- Method for synthesizing ether by catalyzing alcohol through trimethyl halosilane
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The invention discloses a method for synthesizing ether by catalyzing alcohol through trimethyl halosilane. According to the method, under the conditions of air or nitrogen atmosphere, no solvent andno transition metal catalyst, an alcohol compound is directly used as a raw material, trimethyl halosilane is used as a catalyst, and symmetric or asymmetric ether is synthesized through one-step selective dehydration reaction. According to the method, the use of strong acid, strong base and organic primary halides with high toxicity, instability and higher price is avoided, the synthesis steps are shortened, the synthesis efficiency is improved, the reaction has good selectivity, and a target ether product can be obtained preferentially.
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Paragraph 0071-0074
(2020/12/29)
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- Switchable iridium hydride catalysts for controlling selectivity of alcohol oxidation
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Novel pyridyl-triazolylidene iridium(III) hydride complexes have been synthesized through modification of the analogous iridium chloride complexes. The dehydration of alcohols was used to probe the catalytic potential of the iridium chloride compounds and the influence of the electronic modification on the pyridyl-triazolylidene ligand scaffolds. The incorporation of electron donor substituents on the triazolylidene heterocycle considerably enhanced the catalytic activity of the coordinated iridium center towards the catalytic dehydration of alcohols. Moreover, the iridium hydride compounds are switchable catalysts that perform either alcohol dehydration or dehydrogenation. Their selectivity was predictably triggered by the presence or absence of HPF6 in the catalytic reaction.
- Albrecht, Martin,Olivares, Marta
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- Molybdenum (VI)-catalyzed dehydrative construction of C[sbnd]O and C[sbnd]S bonds formation via etherification and thioetherification of alcohols and thiols
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An inexpensive, easily available, environmentally benign, and efficient catalyst molybdenum(VI) dioxo (acetylacetonate)2 was used for the direct oxo- and thioetherification of alcohol. This method endures selective molybdenum catalyzed dehydrative synthesis of symmetrical ethers from benzylic secondary alcohols as well as unsymmetrical ethers from the reaction of benzylic secondary alcohols with primary alcohol. Furthermore, we have been also successful in the synthesis of Aryl thioether by using alcohol and thiols.
- Singh, Rahulkumar Rajmani,Srivastava, Radhey S.,Whittington, Alex
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- H3PMo12O40-catalyzed coupling of diarylmethanols with epoxides/diols/aldehydes toward polyaryl-substituted aldehydes
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A versatile heteropoly acid (H3PMo12O40)-catalyzed coupling of diarylmethanols with epoxides was established for the synthesis of polyaryl-substituted aldehydes. Furthermore, the catalytic system was also suitable for the
- Yang, Guoping,Liu, Yufeng,Li, Ke,Liu, Wei,Yu, Bing,Hu, Changwen
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supporting information
p. 3233 - 3236
(2020/07/21)
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- Fe(III)-Catalyzed, Cyclizative Coupling between 2-Alkynylbenzoates and Carbinols: Rapid Generation of Polycyclic Isocoumarins and Phthalides and Mechanistic Study
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FeCl3 catalyzed, highly regioselective cyclizative coupling of internal alkynes with alcohols has been reported for the rapid synthesis of structurally divergent, complex isocoumarins and phthalides respectively in intermolecular and intramolecular fashion. This strategy exhibited very high substrate scope and efficiency and proceeds through the simultaneous formation of C?O and C?C bonds. Observations from a series of control experiments supported a) the mechanism as Lewis acid catalyzed dual activation of ester and alcohol, b) the role of carbocation for the enhanced rates of cyclization, i. e., activation of alkyne by carbocation, and c) no role of HCl in the reported cascade process. (Figure presented.).
- Gandhi, Soniya,Baire, Beeraiah
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p. 2651 - 2657
(2020/05/25)
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- Benzyl C–O and C–N Bond Construction via C–C Bond Dissociation of Oxime Ester under Visible Light Irradiation
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A photoredox benzyl activation was developed via formidable C(sp3)–C(sp3) bond dissociation of 1-aryl acetone oxime esters, which were easily prepared from benzyl ketones. Further coupling with O- and N- nucleophiles successfully forged important benzyl ether and amines derivatives in one pot. In this process, different substitutions on oxime esters were found compatible and various primary and secondary alcohols and amines, as well as amides showed good performance as nucleophiles. Mechanistic studies by control experiments, electrochemical measurements and in-situ NMR spectra proposed a N–O bond interruption/C–C bond fragmentation/oxidation sequence to provide the key cation intermediate for the next electrophilic SN process. The features of mild condition, short reaction time and broad substrate scope made this new strategy much promising in the transformation of benzyl compounds, which might be valuable in last-stage functionalizations.
- Fan, Xiuwei,Lei, Tao,Liu, Zan,Yang, Xiu-Long,Cheng, Yuan-Yuan,Liang, Ge,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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p. 1551 - 1558
(2019/09/09)
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- Arylboronic Acid Catalyzed C-Alkylation and Allylation Reactions Using Benzylic Alcohols
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The arylboronic acid catalyzed dehydrative C-alkylation of 1,3-diketones and 1,3-ketoesters using secondary benzylic alcohols as the electrophile is reported, forming new C-C bonds (19 examples, up to 98% yield) with the release of water as the only byproduct. The process is also applicable to the allylation of benzylic alcohols using allyltrimethylsilane as the nucleophile (12 examples, up to 96% yield).
- Estopi?á-Durán, Susana,McLean, Euan B.,Donnelly, Liam J.,Hockin, Bryony M.,Taylor, James E.
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supporting information
p. 7547 - 7551
(2020/10/09)
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- Aryl Boronic Acid Catalysed Dehydrative Substitution of Benzylic Alcohols for C?O Bond Formation
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A combination of pentafluorophenylboronic acid and oxalic acid catalyses the dehydrative substitution of benzylic alcohols with a second alcohol to form new C?O bonds. This method has been applied to the intermolecular substitution of benzylic alcohols to form symmetrical ethers, intramolecular cyclisations of diols to form aryl-substituted tetrahydrofuran and tetrahydropyran derivatives, and intermolecular crossed-etherification reactions between two different alcohols. Mechanistic control experiments have identified a potential catalytic intermediate formed between the aryl boronic acid and oxalic acid.
- Estopi?á-Durán, Susana,Donnelly, Liam J.,Mclean, Euan B.,Hockin, Bryony M.,Slawin, Alexandra M. Z.,Taylor, James E.
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supporting information
p. 3950 - 3956
(2019/02/16)
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- Two-component boronic acid catalysis for increased reactivity in challenging Friedel-Crafts alkylations with deactivated benzylic alcohols
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A general and efficient boronic acid catalyzed Friedel-Crafts alkylation of arenes with benzylic alcohols was previously developed for the construction of unsymmetrical diarylmethane products (X. Mo, J. Yakiwchuk, J. Dansereau, J. A. McCubbin and D. G. Hall, J. Am. Chem. Soc., 2015, 137, 9694). Highly electron-deficient benzylic alcohols, however, were ineffective coupling partners due to the increased difficulty of C-O bond ionization. Herein, we report the use of perfluoropinacol as an effective co-catalyst to improve the reactivity of a boronic acid catalyst in the Friedel-Crafts benzylations of electronically deactivated primary and secondary benzylic alcohols. According to spectroscopic studies, it is believed that perfluoropinacol condenses with the arylboronic acid catalyst to form a highly electrophilic and Lewis acidic boronic ester. This in situ formed species enables a more facile ionization of the benzylic alcohols likely through a mode of activation promoted by a Lewis acid assisted hydronium Br?nsted acid generated from the interactions of the transient boronic ester with hexafluoroisopropanol solvent and water.
- Ang, Hwee Ting,Rygus, Jason P. G.,Hall, Dennis G.
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supporting information
p. 6007 - 6014
(2019/06/24)
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- Efficient Thiolation of Alcohols Catalyzed by Long Chained Acid-Functionalized Ionic Liquids under Mild Conditions
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Thioethers as important building blocks have been usually found in organic synthesis. Herein, a series of long chained acid-functionalized ionic liquids derived from pyrrolidine were applied for the thiolation of alcohols to synthesize different compounds containing thioether structures. This kind of ionic liquids exhibited higher efficiency than general ionic liquids based on imidazole, providing up to 99 % yield with [BsCtP][OTf] as the catalyst at room temperature for 0.25 h. The results indicated that the activities of the ionic liquids have relationship with the side chain length of ionic liquids based on pyrrolidine, anions and cations. The catalytic system had wide substrate scope and was applicable for the reaction of aromatic primary and secondary alcohols and thiols including aliphatic and aromatic thiols, benzothiazole-2-thiols and benzooxazole-2-thiols. Besides, there was no obvious change in activity of the catalyst after six runs. Thus, the catalytic system exhibited good recyclability. Additionally, carbocations should be the key intermediate and several functionalized groups of the ionic liquids have synergetic effect for the thiolation.
- Miao, Chengxia,Zhuang, Hongfeng,Wen, Yating,Han, Feng,Yang, Qing-Feng,Yang, Lei,Li, Zhen,Xia, Chungu
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p. 3012 - 3021
(2019/05/16)
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- Practical preparation of diphenylmethyl ethers from 2-diphenylmethoxypyridine using catalytic iron(III) chloride
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A novel facile synthetic method for producing diphenylmethyl (DPM) ethers from 2-diphenylmethoxypyridine was developed. A variety of DPM ethers was successfully achieved with high yield via treatment of alcohols with 2-diphenylmethoxypyridine in the presence of catalytic FeCl3. The procedure is a practical and efficient synthetic procedure to protect various alcohols, and it can be applied to prepare bioactive compounds.
- Tran, Van Hieu,La, Minh Thanh,Kim, Hee-Kwon
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p. 6221 - 6228
(2019/07/04)
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- Innovative approach for the synthesis of N-substituted amides from nitriles and alcohols using propylphosphonic anhydride (T3P) under solvent-free conditions
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Novel and convenient methodology for the construction of N-substituted amide derivatives have been developed from nitriles and alcohols using propylphosphonic anhydride (T3P). This methodology is an alternate approach to the synthesis of amides via Ritter reaction, which is one of the classical methods for the synthesis of N-substituted amides from nitriles and alcohols. In this approach, first T3P activates the alcohol which is then attacked by nitrile to form N-substituted amides. This methodology can also apply for the synthesis of benzhydryl ether. This developed protocol is one of the novel applications of T3P.
- Chaithra, Nagaraju,Mantelingu, Kempegowda,Rangappa, Kanchugarakoppal S.,Rangappa, Shobith,Sandhya, Nagarakere C.,Swarup, Hassan A.
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p. 2106 - 2116
(2020/03/13)
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- Direct Synthesis of Indanes via Iron-Catalyzed Dehydrative Coupling/Friedel–Crafts Cyclization of Two Different Alcohols
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We report herein a novel iron-catalyzed cascade dehydrative coupling/Friedel–Crafts cyclization of two different alcohols, providing a variety of indanes, which are ubiquitous substructures found in natural products, pharmaceuticals, and functional materi
- Sai, Masahiro
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p. 1102 - 1106
(2019/02/14)
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- Non-corrosive heteropolyacid-based recyclable ionic liquid catalyzed direct dehydrative coupling of alcohols with alcohols or alkenes
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A non-corrosive, recyclable and efficient heterogeneous catalyst based on Keggin-type polyoxometalate, i.e., [NMPH]H3[SiW12O40] was developed for the direct dehydrative coupling of alcohols with alcohols (or alkenes) to synthesize various polysubstituted olefins in good to excellent yields. Furthermore, this reaction could be scaled up and the catalyst could be used for seven runs without significant loss of activity. The kinetic competition experiment shows that the C–H bond cleavage might be involved in the rate-determining step.
- Yang, Guo-Ping,Jiang, Nan,Huang, Xian-Qiang,Yu, Bing,Hu, Chang-Wen
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- B(C6F5)3 catalyzed direct nucleophilic substitution of benzylic alcohols: an effective method of constructing C-O, C-S and C-C bonds from benzylic alcohols
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An efficient and general method of nucleophilic substitution of benzylic alcohols catalyzed by non-metallic Lewis acid B(C6F5)3 was developed. The reaction could be carried out under mild conditions and more than 35 exampl
- Meng, Shan-Shui,Wang, Qian,Huang, Gong-Bin,Lin, Li-Rong,Zhao, Jun-Ling,Chan, Albert S. C.
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p. 30946 - 30949
(2018/09/13)
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- Method for catalyzing etherification of benzyl alcohol compounds
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The invention belongs to the field of organic synthesis and discloses a method for catalyzing the etherification of benzyl alcohol compounds. The benzyl alcohol compounds are mixed with an alcohol compound A, and a solvent and tripentafluorophenylborane s
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Paragraph 0038; 0039; 0040
(2018/11/22)
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- Systematic Evaluation of Sulfoxides as Catalysts in Nucleophilic Substitutions of Alcohols
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Herein, a method for the nucleophilic substitution (SN) of benzyl alcohols yielding chloro alkanes is introduced that relies on aromatic sulfoxides as Lewis base catalysts (down to 1.5 mol-%) and benzoyl chloride (BzCl) as reagent. A systematic screening of various sulfoxides and other sulfinyl containing Lewis bases afforded (2-methoxyphenyl)methyl sulfoxide as optimal catalyst. In contrast to reported formamide catalysts, sulfoxides also enable the application of plain acetyl chloride (AcCl) as reagent. In addition, it was demonstrated that weakly electrophilic carboxylic acid chlorides like BzCl promote Pummerer rearrangement of sulfoxides already at room temperature. This side-reaction also provided the explanation, why sulfoxide catalyzed SN-reactions of alcohols do not allow the effective production of aliphatic and electron deficient chloro alkanes. Comparison experiments provided further insight into the reaction mechanism.
- Motsch, Sebastian,Schütz, Christian,Huy, Peter H.
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supporting information
p. 4541 - 4547
(2018/09/13)
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- Direct synthesis of alkenyl iodides: Via indium-catalyzed iodoalkylation of alkynes with alcohols and aqueous HI
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A convenient and efficient indium-catalyzed approach to synthesize alkenyl iodides has been developed through direct iodoalkylation of alkynes with alcohols and aqueous HI under mild conditions. This catalytic protocol offers an attractive approach for th
- Wu, Chao,Wang, Zheng,Hu, Zhan,Zeng, Fei,Zhang, Xing-Yu,Cao, Zhong,Tang, Zilong,He, Wei-Min,Xu, Xin-Hua
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supporting information
p. 3177 - 3180
(2018/05/15)
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- Reaction Route and Mechanism of the Direct N-Alkylation of Sulfonamides on Acidic Mesoporous Zeolite β-Catalyst
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Development of highly active heterogeneous catalysts with strong acidity and mesoporous structure is a highly attractive strategy for organic synthesis. In this study, a mesoporous zeolite beta (HBeta-M) with bulky particle size and strong acidity was synthesized and used in the direct N-alkylation of sulfonamides with alcohols. The strongly acidic HBeta-M had a higher intrinsic activity with initial turnover frequency of 11 × 10-2 s-1 than those of H-form mordenite nanosheets (3.3 × 10-2 s-1) and montmorillonite (4.0 × 10-2 s-1) catalysts. The experiment and characterization results demonstrate that there are two parallel reaction routes on the acidic catalysts. One route is the reaction of benzhydrol with p-toluenesulfonamide (route I). Another route is the reaction of dibenzhydryl ether, arising from route I, with p-toluenesulfonamide (route II), which is found in this work. The reaction rate of route I (13 × 10-3 mol kg-1 s-1) was higher than that of route II (9.8 × 10-3 mol kg-1 s-1) on HBeta-M, but route II predominantly contributed to the formation of the target product with high selectivity. Hereby, a complete reaction mechanism is proposed in this work.
- Fu, Wenqian,Shen, Runsheng,Bai, Enhui,Zhang, Lei,Chen, Qun,Fang, Zhongxue,Li, Guangchao,Yi, Xianfeng,Zheng, Anmin,Tang, Tiandi
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p. 9043 - 9055
(2018/09/11)
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- Ether formation through reductive coupling of ketones or aldehydes catalyzed by a mesoionic carbene iridium complex
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An iridium(iii) Cp? complex containing a triazolylidene-pyridyl C,N-bidentate-coordinating ligand is a very powerful catalyst for the transformation of ketones and aldehydes into symmetrical ethers. This highly efficient reductive coupling proceeds immediately at room temperature and at a low catalyst loading (0.1 mol%) when Ph2SiH2 is used as an additive. Aromatic carbonyl substrates react faster than aliphatic ketones or aldehydes, and the substrate scope suggests some functional group tolerance. Likewise, the condensation of alcohols to symmetrical ethers is catalyzed by this triazolylidene iridium complex, though ether formation is an order of magnitude slower than when starting from the analogous ketone or aldehyde as a substrate, suggesting that alcohols are not potential intermediates in the reductive coupling process. Prolonged reactions or modification of the silane additive lead to ether cleavage and dehydration, thus affording the corresponding olefin. Mechanistic insights and in particular the different reactivities of alcohols and ketones have been exploited to develop a synthetic methodology for the iridium-catalyzed formation of unsymmetrical methyl ethers (R-OMe) in good yields.
- Petronilho,Vivancos,Albrecht
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p. 5766 - 5774
(2017/12/07)
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- Recyclable zinc (II) ionic liquid catalyzed synthesis of azides by direct azidation of alcohols using trimethylsilylazide at room temperature
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A new efficient method has been reported for the synthesis of azides by direct azidation of alcohols with TMSN3 in presence of recyclable task specific ionic liquid (TSIL) [bmim]ZnCl3 as a catalyst in DCM at room temperature. Ionic liquid [bmim]ZnCl3 was synthesized under solvent free conditions and characterized by IR, 1H NMR, 13C NMR and HRMS. The Lewis acidity of catalyst was also examined using IR spectroscopy. The main features of this new methodology are high yields of products, recyclability of catalyst, scalability of reaction to gram scale and short reaction time.
- Singh, Ashima,Singh, Harjinder,Khurana
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p. 2498 - 2502
(2017/05/31)
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- Unprecedented alkylation of silicon enolates with alcohols via carbenium ion formations catalyzed by tin hydroxide-embedded montmorillonite
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The solid acid, tin hydroxide-embedded montmorillonite, catalyzes the unprecedented alkylation of various silicon enolates with primary, secondary and tertiary benzylic alcohols as well as secondary allylic alcohols. The acid catalysis of Sn-Mont was not only higher than that of the other ion-exchanged montmorillonites (M-Mont; M?=?H, Ti, Fe and Al), but also higher than that of the typical homogeneous acid catalysts such as BF3·OEt2, TMSOTf and TfOH.
- Tandiary, Michael Andreas,Asano, Masashi,Hattori, Taiki,Takehira, Satoshi,Masui, Yoichi,Onaka, Makoto
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supporting information
p. 1925 - 1928
(2017/04/27)
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- Exploring the Reducing Ability of Organic Dye (Acr+-Mes) for Fluorination and Oxidation of Benzylic C(sp3)-H Bonds under Visible Light Irradiation
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The excellent oxidizing capability of acridinium-based organic dye (Acr+-Mes) is fully studied in photoredox catalysis. However, its reducing ability is always considered weak for organic transformation. The reducing ability of Acr+-Mes is developed by Selectfluor to achieve effective fluorination and oxidation of benzylic C(sp3)-H bonds under visible light irradiation, which is not available for the direct use of oxidizing ability of excited Acr+-Mes. Mechanistic insights provided strong evidence for the oxidative quenching of Acr+-Mes.
- Xiang, Ming,Xin, Zhi-Kun,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
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supporting information
p. 3009 - 3012
(2017/06/07)
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- Reversible Generation of Labile Secondary Carbocations from Alcohols in the Nanospace of H-Mordenite and Their Long-Lasting Preservation at Ambient Temperature
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Secondary carbocations are rarely observed spectrometrically for prolonged durations at ambient temperatures because of their instability. In this study, when 4,4′-difluorobenzhydrol (1) was mixed with H-mordenite (H-Mor), the 4,4′-difluorodiphenylmethyl cation (2) was generated as the main product, identified by UV-vis and 13C-MAS NMR spectroscopies, and was preserved for over 1 week at ambient temperature. Surprisingly, the polymerization and disproportionation of 1 barely proceeded within the micropores of H-Mor. However, these side reactions prevailed in TfOH and formation of 2 was not observed. Preservation of other secondary carbocations from benzhydrol, 4,4′-dichlorobenzhydrol, and 9-fluorenol was also realized in H-Mor. It was confirmed that the generation of 2 from 1 was controlled by thermodynamic equilibrium rather than kinetic regulations. The equilibrium between 2 and 1 was accompanied by reversible chromism, which could be easily controlled by altering the moisture content in H-Mor. Moreover, novel insights into specific acid catalysis in zeolites densely populated with acid sites on the inner surface of micropores are described herein.
- Masui, Yoichi,Hattori, Taiki,Onaka, Makoto
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supporting information
p. 8612 - 8620
(2017/07/06)
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- Iodine-catalyzed transformation of aryl-substituted alcohols under solvent-free and highly concentrated reaction conditions
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Iodine-catalyzed transformations of alcohols under solvent-free reaction conditions (SFRC) and under highly concentrated reaction conditions (HCRC) in the presence of various solvents were studied in order to gain insight into the behavior of the reaction intermediates under these conditions. Dimerization, dehydration and substitution were the three types of transformations observed with benzylic alcohols. Dimerization and substitution reactions were predominant in the case of primary- and secondary alcohols, whereas dehydration prevailed in the case of tertiary alcohols. The relative reactivity of substituted 1-phenylethanols in I2-catalyzed dimerization under SFRC provided a good Hammett plot ρ+ = -2.8 (r2 = 0.98), suggesting the presence of electron-deficient intermediates with a certain degree of developed charge in the rate-determining step.
- Jereb, Marjan,Vra?i?, Dejan
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p. 747 - 762
(2018/01/17)
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- Microwave assisted benzylation of naphthols and 4-hydroxycoumarin under catalyst & solvent free conditions
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An expeditious and highly practical, microwave assisted benzylation of naphthols and 4-hydroxycoumarin has been developed under catalyst-free & solvent-free conditions. Alcohols undergo heat induced dehydration to form ethers, which collapse reversibly to form the carbocation which was captured immediately by a suitable nucleophile to furnish the benzylated compounds.
- Dada, Ravikrishna,Singh, Garima,Pareek, Abhishek,Kausar, Saeen,Yaragorla, Srinivasarao
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supporting information
p. 3739 - 3742
(2016/07/26)
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- Indium-Triflate-Catalyzed Ritter Reaction in Liquid Sulfur Dioxide
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The use of liquid sulfur dioxide as a reaction solvent facilitates the Ritter reaction between alcohols and nitriles. In(OTf)3 was found to be a viable catalyst for this transformation. The newly developed catalytic conditions for the Ritter reaction were successfully applied to the synthesis of various amides, which were formed in good to excellent yields. The catalytic activation of secondary alcohols for Ritter reactions in liquid sulfur dioxide was also found to be effective.
- Posevins, Daniels,Suta, Krista,Turks, Maris
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supporting information
p. 1414 - 1419
(2016/03/19)
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- Regio- and Stereoselective Synthesis of 1,2,3-Trisubstituted Indanes from Diarylmethanols and Allylamides through Iron(III) Chloride Hexahydrate
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An efficient method for the highly regio- and stereoselective synthesis of 1,2,3-trisubstituted indanes from diarylmethanols and allylamides through iron(III) chloride hexahydrate-catalyzed intermolecular [3+2] cycloaddition reaction is reported. A range
- Li, Yali,Zhang, Lingjuan,Zhang, Zongyao,Xu, Jianbin,Pan, Yixiao,Xu, Conghui,Liu, Lingxian,Li, Zengguang,Yu, Zhiyong,Li, Huanrong,Xu, Lijin
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p. 2148 - 2155
(2016/07/16)
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- A selective, efficient and environmentally friendly method for the oxidative cleavage of glycols
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A catalytic methodology for the oxidative cleavage of vicinal diols is described as an advantageous alternative in terms of the environmental impact on classical methods involving toxic oxidants. The novel strategy is based on the use of dioxomolybdenum(vi) complexes as catalysts and dimethyl sulfoxide (DMSO) as an oxidant and displays high selectivity and a broad scope for glycol cleavage. In addition, the developed system is also useful for the oxidation of acyloins to diketones.
- García, Nuria,Rubio-Presa, Rubén,García-García, Patricia,Fernández-Rodríguez, Manuel A.,Pedrosa, María R.,Arnáiz, Francisco J.,Sanz, Roberto
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supporting information
p. 2335 - 2340
(2016/05/19)
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- Continuous-Flow Multistep Synthesis of Cinnarizine, Cyclizine, and a Buclizine Derivative from Bulk Alcohols
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Cinnarizine, cyclizine, buclizine, and meclizine belong to a family of antihistamines that resemble each other in terms of a 1-diphenylmethylpiperazine moiety. We present the development of a four-step continuous process to generate the final antihistamines from bulk alcohols as the starting compounds. HCl is used to synthesize the intermediate chlorides in a short reaction time and excellent yields. This methodology offers an excellent way to synthesize intermediates to be used in drug synthesis. Inline separation allows the collection of pure products and their immediate consumption in the following steps. Overall isolated yields for cinnarizine, cyclizine, and a buclizine derivative are 82, 94, and 87 %, respectively. The total residence time for the four steps is 90 min with a productivity of 2 mmol h-1. The incredible bulk: Bulk alcohols are converted continuously into chlorides using HCl in a microflow. A reaction network that consists of four steps and two inline separations leads to the continuous preparation of cinnarizine, cyclizine, and a buclizine derivative with yields of 82, 94, and 87 %, respectively. The total residence time for the four steps is 90 min with a productivity of 2 mmol h-1.
- Borukhova, Svetlana,Nol, Timothy,Hessel, Volker
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- An efficient and convenient synthesis of N-substituted amides under heterogeneous condition using Al(HSO4)3 via Ritter reaction
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An efficient and inexpensive synthesis of N-substituted amides from the reaction of aliphatic and aromatic nitriles with various benzylic alcohols (secondary and tertiary) and tert-butyl alcohol by refluxing nitromethane via the Ritter reaction catalyzed by aluminum hydrogen sulfate [Al(HSO4)3] is described. The catalyst which is an air-stable, cost-effective solid acid could be readily recycled by filtration and reused four times without any significant loss of its activity. [Figure not available: see fulltext.]
- Karimian, Elnaz,Akhlaghinia, Batool,Ghodsinia, Sara S.E.
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p. 429 - 439
(2016/03/16)
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- SnBr4-promoted Friedel-Crafts type dehydrative alkylation reaction of diarylmethanols with 2-naphthol derivatives
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Tin(IV) bromide was found to act as an efficient Lewis acid catalyst for the Friedel-Crafts type dehydrative alkylation reaction of diarylmethanols with 2-naphthol derivatives under mild conditions. The effects of the substituents on the substrates were systematically evaluated, and the reaction could be applied to a variety of substrates by tuning the conditions depending on the electronic properties of the starting materials.
- Suzuki, Nobuharu,Tsuchihashi, Shiori,Nakata, Kenya
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p. 1456 - 1459
(2016/03/12)
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- Sulfonated nanohydroxyapatite functionalized with 2-aminoethyl dihydrogen phosphate (HAP@AEPH2-SO3H) as a reusable solid acid for direct esterification of carboxylic acids with alcohols
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Sulfonated nanohydroxyapatite functionalized with 2-aminoethyl dihydrogen phosphate (HAP@AEPH2-SO3H) efficiently catalyzed direct esterification of carboxylic acids and alcohols with high selectivity toward the formation of esters in good to excellent yields. Our results clearly show that HAP@AEPH2-SO3H can be easily recovered by simple filtration and reused for subsequent five runs without any significant impact on yields of products. The main advantage of this methodology is easy and ecofriendly catalyst preparation, easy catalyst separation, practical simplicity, safe reaction conditions, recyclable catalyst and high products yields.
- Siavashi, Narges Yousefi,Akhlaghinia, Batool,Zarghani, Monireh
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p. 5789 - 5806
(2016/06/01)
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- An extremely efficient and green method for the acylation of secondary alcohols, phenols and naphthols with a deep eutectic solvent as the catalyst
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The typical deep eutectic solvent [CholineCl][ZnCl2]3, easily prepared from choline chloride and zinc chloride, is green and useful for the acylation of secondary alcohols, phenols, and naphthols with acid anhydrides. Its efficiency allows the acylation of sterically hindered secondary alcohols and acid anhydrides to proceed in high yield under mild condition. The catalyst is cheap, easy to handle, conveniently synthesized in a single step, and recyclable for several times without significant loss of catalytic activity.
- Nguyen, Hai Truong,Tran, Phuong Hoang
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p. 98365 - 98368
(2016/10/31)
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- Selective synthesis of thioethers in the presence of a transition-metal-free solid Lewis acid
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The synthesis of thioethers starting from alcohols and thiols in the presence of amorphous solid acid catalysts is reported. A silica alumina catalyst with a very low content in alumina gave excellent results in terms of both activity and selectivity also under solvent-free conditions. The reaction rate follows the electron density of the carbinol atom in the substrate alcohol and yields up to 99% and can be obtained for a wide range of substrates under mild reaction conditions.
- Santoro, Federica,Mariani, Matteo,Zaccheria, Federica,Psaro, Rinaldo,Ravasio, Nicoletta
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supporting information
p. 2627 - 2635
(2017/01/09)
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- Organohalide-catalyzed dehydrative O-alkylation between alcohols: A facile etherification method for aliphatic ether synthesis
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Organohalides are found to be effective catalysts for dehydrative O-alkylation reactions between alcohols, providing selective, practical, green, and easily scalable homo- and cross-etherification methods for the preparation of useful symmetrical and unsymmetrical aliphatic ethers from the readily available alcohols. Mechanistic studies revealed that organohalides are regenerated as reactive intermediates and recycled to catalyze the reactions.
- Xu, Qing,Xie, Huamei,Chen, Pingliang,Yu, Lei,Chen, Jianhui,Hu, Xingen
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supporting information
p. 2774 - 2779
(2015/05/27)
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- A combination of trimethylsilyl chloride and hydrous natural montmorillonite clay: An efficient solid acid catalyst for the azidation of benzylic and allylic alcohols with trimethylsilyl azide
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We present a new procedure to convert in situ natural montmorillonite clay into a partially acidified one using a catalytic amount of trimethylsilyl chloride and trace water. We demonstrate that the acidic montmorillonite can catalyze the direct azidation
- Tandiary, Michael A.,Masui, Yoichi,Onaka, Makoto
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p. 15736 - 15739
(2015/02/19)
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- Thiazolium-based catalysts for the etherification of benzylic alcohols under solvent-free conditions
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Thiazolium and imidazolium hybrid materials were prepared by radical reactions between a mercaptopropyl-modified SBA-15 mesoporous silica and bis-vinylthiazolium or bis-vinylimidazolium dibromide salts. These hybrid materials were characterized by several techniques and were employed in the etherification reaction of 1-phenylethanol. Solvent-free conditions at 160C under different gas phases (oxygen, air, nitrogen and argon) were used. The thiazolium-based material displayed excellent performances. Further studies were carried out using unsupported thiazolium salts, with or without a methyl group at the C-2 position of the thiazolium moiety. These studies allowed us to propose a reaction mechanism. The supported thiazolium-based material was successfully used in the etherification reaction of two other benzylic alcohols and also in seven consecutive cycles. This work represents the first use of thiazolium-based compounds as catalysts for the etherification reaction of alcohols.
- Bivona, Lucia Anna,Quertinmont, Fran?ois,Beejapur, Hazi Ahmad,Giacalone, Francesco,Buaki-Sogo, Mireia,Gruttadauria, Michelangelo,Aprile, Carmela
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p. 800 - 810
(2015/03/18)
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- Fe powder catalyzed highly efficient synthesis of alkenyl halides via direct coupling of alcohols and alkynes with aqueous HX as exogenous halide sources
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A simple and efficient catalytic method for the synthesis of alkenyl halides via direct coupling of alcohols and alkynes using aqueous HX (X=Cl, Br) as halide sources has been developed under mild conditions in the presence of Fe powder (1 mol %). In comp
- Yang, Yong-Rong,Zhang, Qiang,Du, Feng-Tian,Ji, Jian-Xin
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supporting information
p. 4304 - 4311
(2015/06/08)
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- Malic acid derivatives as amorphous materials for phase change ink
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Disclosed herein is a component that is substantially amorphous, the component comprising at least one non-ester material and at least one ester of malic acid having a formula of wherein R1 and R2 each, independently of the other, is
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Page/Page column 14
(2015/11/03)
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- Synthesis and Catalytic Use of Gold(I) Complexes Containing a Hemilabile Phosphanylferrocene Nitrile Donor
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Removal of the chloride ligand from [AuCl(1-κP)] (2) containing a P-monodentate 1′-(diphenylphosphanyl)-1-cyanoferrocene ligand (1), by using silver(I) salts affords cationic complexes of the type [Au(1)]X, which exist either as cyclic dimers [Au(1)]2X2 (3a, X=SbF6; 3 c, X=NTf2) or linear coordination polymers [Au(1)]nXn (3 a′, X=SbF6; 3 b′, X=ClO4), depending on anion X and the isolation procedure. As demonstrated for 3 a′, the polymers can be readily cleaved by the addition of donors, such as Cl-, tetrahydrothiophene (tht) or 1, giving rise to the parent compound 2, [Au(tht)(1-κP)][SbF6] (5 a) or [Au(1-κP)2][SbF6] (4 a), respectively, of which the last two compounds can also be prepared by stepwise replacement of tht in [Au(1-κP)2][SbF6]. The particular combination of a firmly coordinated (phosphane) and a dissociable (nitrile) donor moieties renders complexes 3/3′ attractive for catalysis because they can serve as shelf-stable precursors of coordinatively unsaturated AuI fragments, analogous to those that result from the widely used [Au(PR3)(RCN)]X catalysts. The catalytic properties of the Au-1 complexes were evaluated in model annulation reactions, such as the synthesis of 2,3-dimethylfuran from (Z)-3-methylpent-2-en-4-yn-1-ol and oxidative cyclisation of alkynes with nitriles to produce 2,5-disubstituted 1,3-oxazoles. Of the compounds tested (2, 3 a′, 3 b′, 3 a, 4 a and 5 a), the best results were consistently achieved with dimer 3 c, which has good solubility in organic solvents and only one firmly bound donor at the gold atom. This compound was advantageously used in the key steps of annuloline and rosefuran syntheses.
- ?koch, Karel,Císa?ová, Ivana,?těpni?ka, Petr
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p. 15998 - 16004
(2015/11/03)
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- Br?nsted Acid-Catalyzed Reactions of Trifluoroborate Salts with Benzhydryl Alcohols
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Br?nsted acid-catalyzed carbon-carbon bond forming methodology using potassium alkynyl- and alkenyltrifluoroborate salts has been developed. Organotrifluoroborates react with benzhydryl alcohols to afford a broad range of alkynes and alkenes in good to excellent yields. This protocol features good atom economy because organotrifluoroborate salts and alcohols react in a 1:1 ratio. Furthermore, a variety of unprotected functional groups were tolerated under the developed conditions, including amide, aldehyde, free hydroxyl, and carboxylic acid.
- Fisher, Kayla M.,Bolshan, Yuri
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p. 12676 - 12685
(2016/01/09)
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- Copper triflate: An efficient catalyst for direct conversion of secondary alcohols into azides
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A simple, practical, and efficient strategy has been demonstrated for the direct synthesis of organic azides from alcohols using azidotrimethylsilane (TMSN3) as azide source in the presence of copper(II) triflate [Cu(OTf)2]. A variet
- Khedar, Poonam,Pericherla, Kasiviswanadharaju,Kumar, Anil
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p. 515 - 518
(2014/03/21)
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