- Cross-Coupling Reactions of Aryl Halides with Primary and Secondary Aliphatic Alcohols Catalyzed by an O,N,N-Coordinated Nickel Complex
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A synthesis of alkyl aryl ethers was achieved via the cross-coupling of aryl halides with primary and secondary aliphatic alcohols catalyzed by a bench-stable nickel complex supported by a monoanionic O,N,N-tridentate ligand. This nickel-catalyzed reaction proceeds smoothly in the absence of a phosphine ligand, affording alkyl aryl ethers in moderate to good yields. (Figure presented.).
- Hashimoto, Toru,Shiota, Keisuke,Funatsu, Kei,Yamaguchi, Yoshitaka
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supporting information
p. 1625 - 1630
(2021/01/26)
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- Choline Hydroxide as a Versatile Medium for Catalyst-Free O-Functionalization of Phenols
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A versatile synthetic protocol for benzyl phenyl ether preparation via O-alkylation of phenolic oxygen with readily available benzyl derivatives was demonstrated. The newly designed procedure was carried out using an eco-friendly medium, room-temperature ionic liquid (choline hydroxide), under metal- and base-catalyst-free aerobic conditions. The reaction platform was also successfully applied to phenol protection strategy.
- Joo, Seong-Ryu,Kim, Seung-Hoi,Kwon, Gyu-Tae,Park, Soo-Youl
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p. 1200 - 1205
(2020/11/30)
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- An alternative route for boron phenoxide preparation from arylboronic acid and its application for C[sbnd]O bond formation
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An efficient synthetic route to benzyl phenyl ether preparation has been successfully developed via a one-pot synthetic protocol utilizing a combination of arylboronic acids, hydrogen peroxide (H2O2), and benzyl halides. The whole procedure consists of two consecutive reactions, formation of boron phenoxide from arylboronic acids and its nucleophilic attack. A simple operation under mild conditions such as room-temperature ionic liquid (choline hydroxide), aerobic environment, and absence of metal- and base-catalysts has been employed. Expansion to utilize benzyl surrogates was also successfully accomplished.
- Joo, Seong-Ryu,Kim, Seung-Hoi,Lim, In-Kyun
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- En Route to a Practical Primary Alcohol Deoxygenation
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A long-standing scientific challenge in the field of alcohol deoxygenation has been direct catalytic sp3 C-O defunctionalization with high selectivity and efficiency, in the presence of other functionalities, such as free hydroxyl groups and amines widely present in biological molecules. Previously, the selectivity issue had been only addressed by classic multistep deoxygenation strategies with stoichiometric reagents. Herein, we propose a catalytic late-transition-metal-catalyzed redox design, on the basis of dehydrogenation/Wolff-Kishner (WK) reduction, to simultaneously tackle the challenges regarding step economy and selectivity. The early development of our hypothesis focuses on an iridium-catalyzed process efficient mainly with activated alcohols, which dictates harsh reaction conditions and thus limits its synthetic utility. Later, a significant advancement has been made on aliphatic primary alcohol deoxygenation by employing a ruthenium complex, with good functional group tolerance and exclusive selectivity under practical reaction conditions. Its synthetic utility is further illustrated by excellent efficiency as well as complete chemo- and regio-selectivity in both simple and complex molecular settings. Mechanistic discussion is also included with experimental supports. Overall, our current method successfully addresses the aforementioned challenges in the pertinent field, providing a practical redox-based approach to the direct sp3 C-O defunctionalization of aliphatic primary alcohols.
- Dai, Xi-Jie,Li, Chao-Jun
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supporting information
p. 5433 - 5440
(2016/05/19)
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- Choline chloride based deep eutectic solvent as an efficient solvent for the benzylation of phenols
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Deep eutectic solvents (such as the combination of urea and choline chloride) are found to be promising solvent and phase-transfer-media for benzylation of phenol. These methods avoided the complexity of multiple alkylations giving selectively O-alkylated aromatic products. Good to excellent yields of the corresponding benzyl phenyl ether were obtained. The non-toxic, biodegradable, inexpensive, and recyclable nature of DES make this protocol green and cost-effective.
- Singh, Abhilash S.,Shendage, Suresh S.,Nagarkar, Jayashree M.
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p. 7243 - 7246
(2015/02/02)
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- Iridium-catalyzed direct dehydroxylation of alcohols
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Iridium-catalyzed direct dehydroxylation of alcohols with hydrazine was developed through a combination of the oxidation of alcohols and the Wolff-Kishner reduction. This protocol is simple to perform and highly efficient for a series of primary, benzylic and allylic alcohols. Iridium-catalyzed direct dehydroxylation of alcohols with hydrazine is developed through a combination of the oxidation of alcohols and Wolff-Kishner reduction. This protocol is simple to perform and highly efficient for a series of primary alcohols, especially benzylic and allylic ones. Copyright
- Huang, Jian-Lin,Dai, Xi-Jie,Li, Chao-Jun
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supporting information
p. 6496 - 6500
(2013/11/06)
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- Counterattack mode differential acetylative deprotection of phenylmethyl ethers: Applications to solid phase organic reactions
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A counterattack protocol for differential acetylative cleavage of phenylmethyl ether has been developed. The phenylmethyl moiety is liberated as benzyl bromide that is isolated and reused providing advantages in terms of waste minimization/utilization and atom economy. The applicability of this methodology has been extended for solid phase organic reactions with the feasibility of reuse of the solid support.
- Chakraborti, Asit K.,Chankeshwara, Sunay V.
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supporting information; experimental part
p. 1367 - 1370
(2009/07/04)
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- Palladium(0)-mediated rapid methylation and fluoromethylation on carbon frameworks by reacting methyl and fluoromethyl iodide with aryl and alkenyl boronic acid esters: Useful for the synthesis of [11C]CH 3-C-and [18F]FCH2-C-containing PET tracers (PET = positron emission tomography)
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The rapid methylation and fluoromethylation on aryl and alkenyl carbon frameworks by reacting methyl and fluoromethyl iodide with aryl and alkenyl boronates have been studied with the focus on the realization of the synthesis of [11C]CH3- and [18F]FCH2-labeled positron emission tomography (PET) tracers. The coupling of methyl iodide and pinacol phenylboronate (40 equiv) is accomplished in > 91% yield within 5 min at 60 °C under the conditions of [Pd2(dba)3]/P(o- CH3C6H4)3/K2CO 3 (0.5:2:2; dba = di-benzylideneacetone) in DMF. The reaction shows a high generality and is applicable to various types of aryl and alkenyl boronates, giving the corresponding methylated derivatives in high yields (80-99). This reaction is also useful for the rapid incorporation of the fluoromethyl group. Thus, this boron protocol provides a firm chemical basis for the synthesis of 11C- and 18F-incorporated PET tracers and can be used as a complementary method for [11C]methylation together with our previous and ongoing processes using organotributylstannanes.
- Doi, Hisashi,Ban, Ikuya,Nonoyama, Akihito,Sumi, Kengo,Kuang, Chunxiang,Hosoya, Takamitsu,Tsukada, Hideo,Suzuki, Masaaki
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experimental part
p. 4165 - 4171
(2009/12/01)
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- METHOD OF RAPID METHYLATION, KIT FOR PREPARING PET TRACER AND METHOD OF PRODUCING PET TRACER
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It is intended to provide a method of rapid methylation of an aromatic compound or an alkenyl compound, which is capable of obtaining an aromatic compound or an alkenyl compound labeled with a methyl group or a fluoromethyl group under a mild condition rapidly in high yield using an organic boron compound whose toxicity is not so high as a substrate; a kit for preparing a PET tracer to be used in the same, and a method of producing a PET tracer using the same. In an aprotic polar solvent, methyl iodide or X-CH2F (wherein X is a functional group which can be easily released as an anion), an organic boron compound in which an aromatic ring or an alkenyl group is attached to boron are subjected to cross-coupling in the presence of a palladium(0) complex, a phosphine ligand, and a base.
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Page/Page column 9
(2009/07/10)
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- AuCl-catalyzed synthesis of benzyl-protected substituted phenols: A formal [3+3] approach
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(Chemical Equation Presented) A AuCl-catalyzed synthesis of highly substituted, benzyl-protected phenols is developed. This reaction unites enal/enones and benzyl allenyl ether in a [3+3] fashion in two steps, allowing flexibility in phenol synthesis and excellent control of substitution at the benzene ring.
- Huang, Xiaogen,Zhang, Liming
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p. 4627 - 4630
(2008/03/13)
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- Practical synthesis of aromatic ethers by SNAr of fluorobenzenes with alkoxides
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Aromatic fluorines have been substituted by alkoxides in a variety of activated and unactivated aromatic systems.
- Rodriguez, Juan R.,Agejas, Javier,Bueno, Ana B.
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p. 5661 - 5663
(2007/10/03)
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- Synergism of low energy microwave irradiation and solid-liquid phase transfer catalysis for selective alkylation of phenols to phenolic ethers
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A 100% selectivity with an order of magnitude rate enhancement is obtained in the synthesis of phenolic ethers when synergistic combination of solid-liquid phase transfer catalysis and low energy microwave irradiation (MISL-PTC) is employed. As against conventional microwave heating with 600 W power input, the current work demonstrates that a low input of 40 W leads to remarkable enhancement in rates without any destruction of the catalyst.
- Yadav, Ganapati D.,Bisht, Priyal M.
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p. 2885 - 2892
(2007/10/03)
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- New synthetic method of aromatic ethers under microwave irradiation in dry media
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Under microwave irradiation a number of phenols react remarkably fast with a number of primary alkyl halides to give aromatic ethers.
- Bogdal, Dariusz,Pielichowski, Jan,Boron, Adam
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p. 3029 - 3039
(2007/10/03)
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- Highly Efficient and Convenient Methods for the Direct Conversion of Aryl Silyl Ethers and Aryl Acetates into Aryl Alkyl Ethers
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Direct conversion of aryl trialkylsilyl ethers and aryl acetates into the corresponding alkyl-protected phenols such as benzyl and allyl ethers can be conveniently performed by the reaction with alkyl halide in the presence of cesium fluoride and sodium methoxide, respectively, in a one-pot procedure.
- Oriyama, Takeshi,Noda, Kojiro,Yatabe, Kaori
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p. 701 - 703
(2007/10/03)
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- Indenylacetic acid compounds
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4, 5, 6 or 7 Aryl substituted indenyl acetic acids and pharmaceutically acceptable salts, amides and esters thereof. The 4, 5, 6 or 7 aryl substituted indenyl acetic acids have anti-inflammatory, anti-pyretic and analgesic activity. The invention also includes methods for the preparation of these compounds, pharmaceutical compositions and methods of treating inflammation by administering these particular compounds to patients.
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