- Visible light mediated synthesis of 6H-benzo[c]chromenes: transition-metal-free intramolecular direct C-H arylation
-
A synthetic approach towards the 6H-benzo[c]chromene ring under visible light and transition-metal-free conditions has been developed. Benzochromenes are synthesized from the corresponding (2-halobenzyl) phenyl ethers or (2-halophenyl) benzyl ethers using
- Budén, María E.,Heredia, Micaela D.,Puiatti, Marcelo,Rossi, Roberto A.
-
p. 228 - 239
(2021/12/29)
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- Direct Deamination of Primary Amines via Isodiazene Intermediates
-
We report here a reaction that selectively deaminates primary amines and anilines under mild conditions and with remarkable functional group tolerance including a range of pharmaceutical compounds, amino acids, amino sugars, and natural products. An anomeric amide reagent is uniquely capable of facilitating the reaction through the intermediacy of an unprecedented monosubstituted isodiazene intermediate. In addition to dramatically simplifying deamination compared to existing protocols, our approach enables strategic applications of iminium and amine-directed chemistries as traceless methods. Mechanistic and computational studies support the intermedicacy of a primary isodiazene which exhibits an unexpected divergence from previously studied secondary isodiazenes, leading to cage-escaping, free radical species that engage in a chain, hydrogen-atom transfer process involving aliphatic and diazenyl radical intermediates.
- Berger, Kathleen J.,Driscoll, Julia L.,Yuan, Mingbin,Dherange, Balu D.,Gutierrez, Osvaldo,Levin, Mark D.
-
supporting information
p. 17366 - 17373
(2021/11/04)
-
- Nickel-Catalyzed Hydrodeoxygenation of Aryl Sulfamates with Alcohols as Mild Reducing Agents
-
The nickel-catalyzed hydrodeoxygenation of aryl sulfamates has been developed with alcohols as mild reductants. A variety of functional groups and heterocycles were tolerated in this reaction system to give the desired products in high yields. In addition, the gram-scale process and stepwise cine-substitution were also achieved with high efficiency.
- Matsuo, Kasumi,Kuriyama, Masami,Yamamoto, Kosuke,Demizu, Yosuke,Nishida, Koyo,Onomura, Osamu
-
p. 4449 - 4460
(2021/08/25)
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- Radical Anion Promoted Chemoselective Cleavage of Csp2-S Bond Enables Formal Cross-Coupling of Aryl Methyl Sulfones with Alcohols
-
A novel formal cross-coupling of aryl methyl sulfones and alcohols affording alkyl aryl ethers via an SRN1 pathway is developed. Two marketed antitubercular drugs were efficiently prepared employing this approach as the key step. A dimsyl-anion initiated radical chain process was revealed as the major pathway. DFT calculations indicate that the formation of a radical anion via nucleophilic addition of alkoxide to the aryl radical is the key step in determining the observed chemoselectivity.
- Bai, Jixiang,Wang, Tianxin,Dai, Botao,Liu, Qingchao,Yu, Peiyuan,Jia, Tiezheng
-
supporting information
p. 5761 - 5765
(2021/08/16)
-
- Method for synthesizing aryl benzyl ether compound
-
The invention discloses a method for synthesizing aryl benzyl ether compounds, which comprises the following steps: by using an iron (III) complex containing 1, 3-di-tert-butyl imidazole cations and having a molecular formula of [(tBuNCH = CHNtBu) CH] [FeBr4] as a catalyst and di-tert-butyl peroxide as an oxidant, carrying out oxidative coupling reaction on phenolic compounds and toluene compounds to synthesize the corresponding aryl benzyl ether compounds. The method is the first example for preparing the aryl benzyl ether compound through the oxidative coupling reaction of the phenolic compound and the toluene compound, which is realized by an iron-based catalyst, and has the advantages of atom economy, environmental friendliness and good substrate applicability.
- -
-
Paragraph 0030; 0031; 0041
(2021/04/14)
-
- Application of iron (III) complex containing 1,3-di-tert-butyl imidazole cations in synthesis of aryl benzyl ether compounds
-
The invention discloses an application of an iron (III) complex containing 1,3-di-tert-butyl imidazole cations in synthesis of aryl benzyl ether compounds, and particularly relates to a method for synthesizing corresponding aryl benzyl ether compounds by taking di-tert-butyl peroxide as an oxidizing agent and carrying out oxidative coupling reaction on phenolic compounds and toluene compounds. According to the method, the iron (III) complex is used as the catalyst for the first time, and oxidative coupling of the phenolic compound and the toluene compound is realized. The method is the first oxidative coupling reaction of phenolic compounds and benzyl C(sp3)-H bonds, and a new method is provided for synthesizing aryl benzyl ether compounds. Compared with an existing synthesis method, the method provided by the invention avoids using toxic and polluting halogenated hydrocarbon and strong base, has better atom economy, and conforms to the development concept of green synthetic chemistry.
- -
-
Paragraph 0027-0029
(2021/04/26)
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- A facile and versatile electro-reductive system for hydrodefunctionalization under ambient conditions
-
A general electrochemical system for reductive hydrodefunctionalization is described, employing the inexpensive and easily available triethylamine (Et3N) as a sacrificial reductant. This protocol is characterized by facile operation, sustainable conditions, and exceptionally wide substrate scope covering the cleavage of C-halogen, N-S, N-C, O-S, O-C, C-C and C-N bonds. Notably, the selectivity and capability of reduction can be conveniently switched by simple incorporation or removal of an alcohol as a co-solvent.
- Huang, Binbin,Guo, Lin,Xia, Wujiong
-
p. 2095 - 2103
(2021/03/26)
-
- Transition-Metal-Free and Base-Promoted Carbon-Heteroatom Bond Formation via C-N Cleavage of Benzyl Ammonium Salts
-
A facile and general method for constructing carbon-heteroatom (C-P, C-O, C-S, and C-N) bonds via C-N cleavage of benzyl ammonium salts under transition-metal-free conditions was reported. The combination of t-BuOK and 18-crown-6 enabled a wide range of substituted benzyl ammonium salts to couple readily with different kinds of heteroatom nucleophiles, i.e. hydrogen phosphoryl compounds, alcohols, thiols, and amines. Good functional group tolerance was demonstrated. The scale-up reaction and one-pot synthesis were also successfully performed.
- Liu, Long,Tang, Yuanyuan,Wang, Kunyu,Huang, Tianzeng,Chen, Tieqiao
-
p. 4159 - 4170
(2021/03/09)
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- Towards ortho-selective electrophilic substitution/addition to phenolates in anhydrous solvents
-
Alkyl-substituted Li-phenolates with BnBr in water solution lead to a mixture of o- and p-Bn-substituted phenols together with a substantial amount of phenol Bn ether. In CPME, and especially in toluene with 1–2 equivalents of ether or alcohol additives, ortho-selective alkylation is achieved. In the case of o,o,p-tri- and o,o-di-substituted phenols dearomatization occurs affording o-Bn-substituted alkyl cyclohexadienones with yields up to 92% with an o/p ratio up to 90/1.
- Lopu?anskaja, Eleana,Kooli, Anni,Paju, Anne,J?rving, Ivar,Lopp, Margus
-
-
- A Bottleable Imidazole-Based Radical as a Single Electron Transfer Reagent
-
Reduction of 1,3-bis(2,6-diisopropylphenyl)-2,4-diphenyl-1H-imidazol-3-ium chloride (1) resulted in the formation of the first structurally characterized imidazole-based radical 2. 2 was established as a single electron transfer reagent by treating it with an acceptor molecule tetracyanoethylene. Moreover, radical 2 was utilized as an organic electron donor in a number of organic transformations such as in activation of an aryl-halide bond, alkene hydrosilylation, and in catalytic reduction of CO2 to methoxyborane, all under ambient temperature and pressure.
- Das, Arpan,Ahmed, Jasimuddin,Rajendran,Adhikari, Debashis,Mandal, Swadhin K.
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p. 1246 - 1252
(2020/12/21)
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- SOLVENT-FREE CROSS-COUPLING REACTION, AND PRODUCTION METHOD USING SAID REACTION
-
Disclosed is a cross-coupling reaction method which forms a chemical bond selected from C—N, C—B, C—C, C—O and C—S bonds, the method comprising: preparing an aromatic compound (1) having a leaving group;preparing a compound (2) capable of undergoing a cross-coupling reaction selected from an aromatic amino compound (2-1), a diboronic acid ester or the like (2-2), an aromatic boronic acid or the like (2-3), an aromatic compound (2-4) having a hydroxyl group and an aromatic compound (2-5) having a thiol group; andperforming a cross-coupling reaction of the compound (1) with the compound (2) in the presence of a palladium catalyst, a base and a compound (4) having a carbon-carbon double bond or a carbon-carbon triple bond, in the absence of a solvent.
- -
-
Paragraph 0336-0337
(2021/12/30)
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- CoII Immobilized on Aminated Magnetic-Based Metal–Organic Framework: An Efficient Heterogeneous Nanostructured Catalyst for the C–O Cross-Coupling Reaction in Solvent-Free Conditions
-
Abstract: In this paper, we report the synthesis of Fe3O4?AMCA-MIL53(Al)-NH2-CoII NPs based on the metal–organic framework structures as a magnetically separable and environmentally friendly heterogeneous nanocatalyst. The prepared nanostructured catalyst efficiently promotes the C–O cross-coupling reaction in solvent-free conditions without the need for using toxic solvents and/or expensive palladium catalyst. Graphic Abstract: [Figure not available: see fulltext.].
- Mohammadinezhad, Arezou,Akhlaghinia, Batool
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p. 332 - 352
(2020/01/11)
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- Choline Hydroxide as a Versatile Medium for Catalyst-Free O-Functionalization of Phenols
-
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
-
p. 1200 - 1205
(2020/11/30)
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- A rings-in-pores net: Crown ether-based covalent organic frameworks for phase-transfer catalysis
-
We herein present a new family of crown ether-based covalent organic frameworks (CE-COFs) for the first time. The CE-COFs show excellent phase-transfer catalytic performance in various nucleophilic substitution reactions.
- Guo, Wen-Di,Hu, Bingwen,Jiang, Wei-Ling,Lou, Xiaobing,Ma, De-Li,Qi, Qiao-Yan,Shen, Ji-Chuang,Shen, Ming,Yang, Hai-Bo,Zhao, Xin
-
supporting information
p. 595 - 598
(2020/01/29)
-
- An alternative route for boron phenoxide preparation from arylboronic acid and its application for C[sbnd]O bond formation
-
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
-
-
- Hydrodebromination of Aromatic Bromides Catalyzed by Unsupported Nanoporous Gold: Heterolytic Cleavage of Hydrogen Molecule
-
Unsupported nanoporous gold (AuNPore) is a highly efficient, practically applicable, and recyclable catalyst for hydrodebromination of aromatic bromides. The AuNPore-catalyzed hydrodebromination of aromatic bromides proceeded smoothly at relatively low hydrogen pressure and temperature to achieve good to excellent yields of the corresponding non-bromine variants. The selective hydrodebromination reaction occurred exclusively in the coexistence of chlorine atom. For the first time, a mechanistic study revealed that the H?H bond splits in a heterolysis manner on the surface of AuNPore to generate Au?H hydride species.
- Bao, Ming,Feng, Xiujuan,Yamamoto, Yoshinori,Zhang, Sheng,Zhao, Yuhui
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p. 4951 - 4957
(2020/09/09)
-
- Erratum: Synthesis of organic super-electron-donors by reaction of nitrous oxide with n-heterocyclic olefins (Journal of the American Chemical Society (2019) 141:43 (17112?17116) DOI: 10.1021/jacs.9b10660)
-
We realized that the legend of Figure S20 in the Supporting Information contains mistakes. The UV-vis spectrum of 5a was recorded at a lower concentration than indicated (0.023 mM instead of 0.06 mM), and the solvent used for the measurements was DMSO and not THF. The conclusions are not affected by this error. The Supporting Information has been corrected and is available.
- Eymann, Léonard Y. M.,Varava, Paul,Shved, Andrei M.,Curchod, Basile F. E.,Liu, Yizhu,Planes, Ophélie M.,Sienkiewicz, Andrzej,Scopelliti, Rosario,Fadaei Tirani, Farzaneh,Severin, Kay
-
supporting information
p. 1112 - 1112
(2020/02/13)
-
- Catalytic Transfer Hydrodebenzylation with Low Palladium Loading
-
A highly-efficient catalytic system for hydrodebenzylation reaction is described. The cleavage of O-benzyl and N-benzyl protecting groups was performed using an uncommonly low palladium loading (0.02–0.3 mol%; TON up to 5000) in a relatively short reaction time. The approach was used for a variety of substrates including pharmaceutically important precursors, and gram-scale deprotection reaction was shown. Transfer conditions together with easy-to-make Pd/C catalyst are the key features of this debenzylation scheme. (Figure presented.).
- Yakukhnov, Sergey A.,Ananikov, Valentine P.
-
supporting information
p. 4781 - 4789
(2019/09/16)
-
- Catalytic hydrodebromination of aryl bromides by cobalt tetra-butyl porphyrin complexes with EtOH
-
Hydrodebromination of aryl bromides catalyzed by electron rich and sterically unhindered cobalt 5,10,15,20-tetrabutylporphyrin was achieved at mild conditions in good yields employing EtOH as the hydrogen source. The catalytic efficiency was enhanced compared with previously reported by cobalt tetra-aryl porphyrin catalysts. A revised mechanism of single electron transfer was proposed.
- Chen, Chen,Zuo, Huiping,Chan, Kin Shing
-
p. 510 - 517
(2019/01/04)
-
- Hydrosilylation of carbonyl and carboxyl groups catalysed by Mn(i) complexes bearing triazole ligands
-
Manganese(i) complexes bearing triazole ligands are reported as catalysts for the hydrosilylation of carbonyl and carboxyl compounds. The desired reaction proceeds readily at 80 °C within 3 hours at catalyst loadings as low as 0.25 to 1 mol%. Hence, good to excellent yields of alcohols could be obtained for a wide range of substrates including ketones, esters, and carboxylic acids illustrating the versatility of the metal/ligand combination.
- Martínez-Ferraté, Oriol,Chatterjee, Basujit,Werlé, Christophe,Leitner, Walter
-
p. 6370 - 6378
(2019/11/20)
-
- Base-Mediated O-Arylation of Alcohols and Phenols by Triarylsulfonium Triflates
-
A mild and efficient protocol for O-arylation of alcohols and phenols (ROH) by triarylsulfonium triflates was developed under transition-metal-free conditions. Various alcohols, including primary, secondary and tertiary, and phenols bearing either electron-donating or electron-withdrawing groups on the aryl rings were smoothly converted to form the corresponding aromatic ethers in moderate to excellent yields. The reactions were conducted at 50 or 80 °C for 24 h in the presence of a certain base and showed good functional group tolerance. The base-mediated arylation with asymmetric triarylsulfonium salts could selectively transfer the aryl groups of sulfoniums to ROH, depending on their inherent electronic nature. The mechanistic studies revealed that the reaction might proceed through the nucleophilic attack of the in situ formed alkoxy or phenoxy anions at the aromatic carbon atoms of the C?S bonds of triarylsulfonium cations to furnish the target products.
- Ming, Xiao-Xia,Tian, Ze-Yu,Zhang, Cheng-Pan
-
supporting information
p. 3370 - 3379
(2019/11/03)
-
- Decarbonylation through Aldehydic C-H Bond Cleavage by a Cationic Iridium Catalyst
-
We report the decarbonylation of aldehydes through an aldehydic C-H bond cleavage catalyzed by a cationic iridium/bisphosphine catalyst. The reaction proceeds under relatively mild conditions to give the corresponding hydrocarbon products in moderate to high yields. In addition, this cationic iridium catalyst system can be applied to an asymmetric hydroacylation of ketones.
- Shirai, Tomohiko,Sugimoto, Kazuki,Iwasaki, Masaya,Sumida, Ryuki,Fujita, Harunori,Yamamoto, Yasunori
-
supporting information
p. 972 - 976
(2019/05/10)
-
- Palladium-catalyzed tandem isomerization/hydrothiolation of allylarenes
-
Herein we report a tandem olefin migration/hydrothiolation of allyl benzenes facilitated by an in situ generated palladium hydride. A catalyst system composed of palladium acetate and bidentate ligand dtbpx (1,2-bis(di-tert-butylphosphinomethyl)benzene in the presence of catalytic amounts of triflic acid led to the tandem transformation, which furnished benzylic thioethers. The reaction exhibits high regioselectivity and can be conducted under mild conditions. The robustness of the catalyst is displayed through reactions with coordinating thiols.
- Kathe, Prasad M.,Fleischer, Ivana
-
supporting information
p. 2213 - 2217
(2019/03/26)
-
- Ligand-free palladium catalyzed Ullmann biaryl synthesis: 'Household' reagents and mild reaction conditions
-
A palladium catalysed Ullmann biaryl synthesis has been developed using hydrazine hydrate as the reducing reagent at room temperature. The combination of Pd(OAc)2 and hydrazine hydrate works smoothly for the coupling of both electron-rich and electron-deficient aryl iodides, as well as hetero-aryl iodides, leading to a wide range of biaryls in good to excellent yields. The reaction requires only 1 mol% Pd(OAc)2 and the in situ generated palladium naoparticles are found to be active catalysts.
- Gong, Xinchi,Wu, Jie,Meng, Yunge,Zhang, Yulan,Ye, Long-Wu,Zhu, Chunyin
-
supporting information
p. 995 - 999
(2019/03/12)
-
- Fe3O4@SiO2-copper sucrose xanthate as a green nanocatalyst for N-, O- and S-arylation
-
Formation of C(sp2)–X bonds was carried out using a Fe3O4@SiO2-copper(I) sucrose xanthate nanoparticle catalyst with the aid of the copper(I) xanthate moiety in the catalyst which was prepared from the reaction between sucrose and carbon disulfide through an alkaline medium via the traditional Zeise approach. Various techniques were employed for the characterization of these novel nanoparticles. Three sorts of heteroatoms, N, O and S, successfully underwent heteroatom arylation to produce secondary or tertiary amines, ethers and thioethers, respectively.
- Radfar, Iman,Kazemi Miraki, Maryam,Esfandiary, Naghmeh,Ghandi, Leila,Heydari, Akbar
-
-
- Nickel-catalysed C–O bond reduction of 2,4,6-triaryloxy-1,3,5-triazines in 2-methyltetrahydrofuran
-
A nickel-catalysed reduction of phenol derivatives activated by 2,4,6-trichloro-1,3,5-triazine (TCT) in ecofriendly 2-methyltetrahydrofuran (2-MeTHF) is described. The phenol-TCT derivatives were readily prepared using grinding method in short time without further purification. This catalytic system allowed the facile C–O cleavage of phenol-TCT derivatives under mild reaction conditions with high efficiency and good functional group tolerance. Gram-scale reaction was also achieved. Particularly, sequential functionalization of phenol-TCT derivatives followed by C–O bond reduction could also be realized, affording the high value-added products in moderate to good yields.
- Wang, Yaoyao,Shen, Jun,Chen, Qun,Wang, Liang,He, Mingyang
-
p. 409 - 412
(2018/10/02)
-
- Method for selectively catalyzing hydrogenolysis of aryl group C-Br bond using nano porous metal
-
The invention belongs to the fields of pharmaceutical chemical intermediate and related chemistry, and provides a method for selectively catalyzing the hydrogenolysis of an aryl group C-Br bond usingnano porous metal. The method comprises the steps that (1), a bromine-substituted aromatic compound, a nano porous metal catalyst, alkali and a solvent are added to a reaction kettle, hydrogen is added, and heating and stirring are conducted; (2), reaction liquid obtained in step (1) is added to water after reaction is completed, extracting is conducted, and a solvent is removed by vacuum distillation to obtained a target product debromination aromatic compound. Compared with the prior art, the nano porous metal catalyst is taken as a catalyst, the catalyst can be conveniently recycled, the catalyst can be reused after simple filtering and cleaning, the catalyst has a stable structure and high catalytic activity, the catalytic activity is not significantly reduced after being reused for multiple times, and the possibility of industrialization of the catalyst is achieved.
- -
-
Paragraph 0070; 0072; 0073; 0074-0081
(2019/04/26)
-
- Synthesis of Organic Super-Electron-Donors by Reaction of Nitrous Oxide with N-Heterocyclic Olefins
-
The reaction of nitrous oxide (N2O) with N-heterocyclic olefins (NHOs) results in cleavage of the N-O bond and formation of azo-bridged NHO dimers. The latter represent very electron-rich compounds with a low ionization energy. Cyclic voltammetry studies show that the dimers can be classified as new organic super-electron-donors, with a reducing power similar to what is found for tetraazafulvalene derivatives. Mild oxidants are able to convert the neutral dimers into radical cations, which can be isolated. Further oxidation gives stable dications.
- Eymann, Leónard Y. M.,Varava, Paul,Shved, Andrei M.,Curchod, Basile F. E.,Liu, Yizhu,Planes, Ophélie M.,Sienkiewicz, Andrzej,Scopelliti, Rosario,Fadaei Tirani, Farzaneh,Severin, Kay
-
supporting information
p. 17112 - 17116
(2019/11/03)
-
- Metal-Free C-O Bond Functionalization: Catalytic Intramolecular and Intermolecular Benzylation of Arenes
-
A catalytic, metal-free intramolecular rearrangement of benzyl phenyl ethers using nitrosonium salt as a catalyst is described. The optimized reaction conditions enabled a catalytic and metal-free Friedel-Crafts alkylation reaction with benzylic alcohols, producing water as the stoichiometric byproduct. A comprehensive scope (>50 examples) for both approaches and application in drug synthesis were demonstrated. Mechanistic studies suggest a Lewis acid-based mechanism for the metal-free Friedel-Crafts reaction.
- Bering, Luis,Jeyakumar, Kirujan,Antonchick, Andrey P.
-
supporting information
p. 3911 - 3914
(2018/07/22)
-
- Nickel-catalyzed C-O bond reduction of aryl and benzyl 2-pyridyl ethers
-
The reduction of aryl and benzyl 2-pyridyl ethers with sodium isopropoxide was carried out via nickel-catalyzed C-OPy bond cleavage, giving reductive products in reasonable to excellent yields. This method allowed the 2-pyridyloxy group to be directly rem
- Li, Jing,Wang, Zhong-Xia
-
supporting information
p. 2138 - 2141
(2018/03/06)
-
- Decarboxylative C(sp3)?O Cross-Coupling
-
Alkyl aryl ethers are an important class of compounds in medicinal and agricultural chemistry. Catalytic C(sp3)?O cross-coupling of alkyl electrophiles with phenols is an unexplored disconnection strategy to the synthesis of alkyl aryl ethers, with the potential to overcome some of the major limitations of existing methods such as C(sp2)?O cross-coupling and SN2 reactions. Reported here is a tandem photoredox and copper catalysis to achieve decarboxylative C(sp3)?O coupling of alkyl N-hydroxyphthalimide (NHPI) esters with phenols under mild reaction conditions. This method was used to synthesize a diverse set of alkyl aryl ethers using readily available alkyl carboxylic acids, including many natural products and drug molecules. Complementarity in scope and functional-group tolerance to existing methods was demonstrated.
- Mao, Runze,Balon, Jonathan,Hu, Xile
-
supporting information
p. 13624 - 13628
(2018/09/25)
-
- A general copper-based photoredox catalyst for organic synthesis: Scope, application in natural product synthesis and mechanistic insights
-
Organic transformations can broadly be classified into four categories including cationic, anionic, pericyclic and radical reactions. While the last category has been known for decades to provide remarkably efficient synthetic pathways, it has long been hampered by the need for toxic reagents, which considerably limited its impact on chemical synthesis. This situation has come to an end with the introduction of new concepts for the generation of radical species, photoredox catalysis – which simply relies on the use of a catalyst that can be activated upon visible light irradiation – certainly being the most efficient one. The state-of-the-art catalysts mostly rely on the use of ruthenium and iridium complexes and organic dyes, which still considerably limits their broad implementation in chemical processes: alternative readily available catalysts based on inexpensive, environmentally benign base metals are therefore strongly needed. Furthermore, expanding the toolbox of methods based on photoredox catalysis will facilitate the discovery of new light-mediated transformations. This article details the use of a simple copper complex which, upon activation with blue light, can initiate a broad range of radical reactions.
- Deldaele, Christopher,Michelet, Bastien,Baguia, Hajar,Kajouj, Sofia,Romero, Eugenie,Moucheron, Cecile,Evano, Gwilherm
-
p. 621 - 629
(2018/10/04)
-
- Merging Photoredox with Br?nsted Acid Catalysis: The Cross-Dehydrogenative C?O Coupling for sp3 C?H Bond Peroxidation
-
A photoredox and Br?nsted acid synergistically catalyzed cross-dehydrogenative C?O coupling reaction is developed in which isochroman peroxyacetals are formed through sp3 C?H bond peroxidation. The reported method is characterized by its extremely mild reaction conditions, excellent yields, and broad substrate scope. An oxocarbenium ion p-chlorobenzenesulfonate was speculated to be the reactive intermediate. The role of hemiacetals and oxygenated dimers on the effective stabilization of the oxocarbenium ion was investigated; the presence of acid appeared to establish equilibrium between hemiacetals and oxygenated dimers with the oxocarbenium ion pairs. The broad applicability of the method highlights the potential of the protocol for molecule synthesis.
- Xia, Qing,Wang, Qiang,Yan, Changcun,Dong, Jianyang,Song, Hongjian,Li, Ling,Liu, Yuxiu,Wang, Qingmin,Liu, Xiangming,Song, Haibin
-
supporting information
p. 10871 - 10877
(2017/08/18)
-
- Direct C-H Cyanation of Arenes via Organic Photoredox Catalysis
-
Methods for the direct C-H functionalization of aromatic compounds are in demand for a variety of applications, including the synthesis of agrochemicals, pharmaceuticals, and materials. Herein, we disclose the construction of aromatic nitriles via direct C-H functionalization using an acridinium photoredox catalyst and trimethylsilyl cyanide under an aerobic atmosphere. The reaction proceeds at room temperature under mild conditions and has proven to be compatible with a variety of electron-donating and -withdrawing groups, halogens, and nitrogen- and oxygen-containing heterocycles, as well as aromatic-containing pharmaceutical agents.
- McManus, Joshua B.,Nicewicz, David A.
-
supporting information
p. 2880 - 2883
(2017/03/11)
-
- Hydrodehalogenation of Haloarenes by a Sodium Hydride–Iodide Composite
-
A simple protocol for hydrodebromination and -deiodination of halo(hetero)arenes was enabled by sodium hydride (NaH) in the presence of lithium iodide (LiI). Mechanistic studies showed that an unusual concerted nucleophilic aromatic substitution operates in the present process.
- Ong, Derek Yiren,Tejo, Ciputra,Xu, Kai,Hirao, Hajime,Chiba, Shunsuke
-
supporting information
p. 1840 - 1844
(2017/02/05)
-
- Mitsunobu Reaction Using Basic Amines as Pronucleophiles
-
A novel protocol for extending the scope of the Mitsunobu reaction to include amine nucleophiles to form C-N bonds through the utilization of N-heterocyclic phosphine-butane (NHP-butane) has been developed. Both aliphatic alcohols and benzyl alcohols are suitable substrates for C-N bond construction. Various acidic nucleophiles such as benzoic acids, phenols, thiophenol, and secondary sulfonamide also provide the desired products of esters, ethers, thioether, and tertiary sulfonamide with 43-93% yields. Importantly, C-N bond-containing pharmaceuticals, Piribedil and Cinnarizine, have been synthesized in one step from the commercial amines under this Mitsunobu reaction system.
- Huang, Hai,Kang, Jun Yong
-
p. 6604 - 6614
(2017/07/15)
-
- Ruthenium-Catalyzed Dehydrogenative Decarbonylation of Primary Alcohols
-
Dehydrogenative decarbonylation of a primary alcohol involves the release of both dihydrogen and carbon monoxide to afford the by one carbon unit shorter product. The transformation has now been achieved with a ruthenium-catalyzed protocol by using the complex Ru(COD)Cl2 and the hindered monodentate ligand P(o-tolyl)3 in refluxing p-cymene. The reaction can be applied to both benzylic and long-chain linear aliphatic alcohols. The intermediate aldehyde can be observed during the transformation, which is therefore believed to proceed through two separate catalytic cycles involving first dehydrogenation of the alcohol and then decarbonylation of the resulting aldehyde.
- Mazziotta, Andrea,Madsen, Robert
-
p. 5417 - 5420
(2017/10/06)
-
- Alkyl Carbon-Oxygen Bond Cleavage of Aryl Alkyl Ethers by Iridium-Porphyrin and Rhodium-Porphyrin Complexes in Alkaline Media
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Alkyl C-O bond cleavage in aryl alkyl ethers was achieved with Rh(ttp)Cl (1a; ttp = 5,10,15,20-tetrakis(p-tolyl)porphyrinato dianion) together with competitive alkyl C-H bond activation in alkaline media. In contrast, selective alkyl C-O bond cleavage occurred with the iridium-porphyrin Ir(ttp)(CO)Cl (1b)/KOH. Mechanistic investigations indicate the coexistence of MI(ttp)- and M2II(ttp)2 (M = Rh, Ir) under basic conditions. With a weaker Rh(ttp)-Rh(ttp) bond, RhII(ttp)· metalloradical exists in an appreciable amount to cleave the alkyl C-H bond, competing with the alkyl C-O bond cleavage via RhI(ttp)-. In contrast, the more nucleophilic IrI(ttp)- cleaves the alkyl C-O bond exclusively.
- Chen, Chen,Chan, Kin Shing
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p. 3456 - 3464
(2017/10/03)
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- Deoxidizing reduction method for phenolic compound
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The invention discloses a deoxidizing reduction method for a phenolic compound. The method comprises the following steps: reacting the phenolic compound with sulfuryl fluoride, thereby generating aryl fluorosulfonate; adding palladium acetate as a catalyst, 1,3-diphenylphosphine propane ligand and NH3/HCOOH as transferring hydrogen reducing agent; acquiring the corresponding arene after completing the reaction. On the basis of the molar weight of the raw material phenol, the dosage of the palladium acetate catalyst is 2mol%-5mol%; the dosage of the 1,3-diphenylphosphine propane ligand is 1.2 times of the dosage of the palladium acetate catalyst; the removal of monomolecular hydroxy requires 4 times of equivalent transferring hydrogen reducing agent. Most reagents used according to the invention are low-cost and are easily acquired. The dosage of the high-cost palladium acetate catalyst is less and the low-toxicity dimethyl sulfoxide is used as the solvent, so that the method is green and economical. Besides, the reaction time according to the invention is short and the whole process requires no heating and can be completed under room temperature, so that the method has the characteristics of high speed, energy-saving effect, and the like.
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Paragraph 0032; 0033; 0034
(2017/11/04)
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- A facile and mild Pd-catalyzed one-pot process for direct hydrodeoxygenation (HDO) phenols to arenes through a ArOSO2F intermediates transformation
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A practical one-pot process for hydrodeoxygenation (HDO) of phenolic derivatives to their corresponding arenes was developed. This method provided a facile route to upgrading bio-oil. The substrate scope of this protocol was wide, complicated and multi-phenolic compounds were also smoothly hydrodeoxygenated to their corresponding arenes.
- Wang, Xiao-Yan,Leng, Jing,Wang, Shi-Meng,Asiri, Abdullah M.,Marwani, Hadi M.,Qin, Hua-Li
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supporting information
p. 2340 - 2343
(2017/05/29)
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- Oxidation-Reduction Condensation of Diazaphosphites for Carbon-Heteroatom Bond Formation Based on Mitsunobu Mechanism
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An efficient oxidation-reduction condensation reaction of diazaphosphites with various nonacidic pronucleophiles in the presence of DIAD as a weak oxidant has been developed for carbon-heteroatom bond formation. This mild process affords structurally diverse tertiary amines, secondary amines, esters, ethers, and thioethers in moderate to excellent yields. The selective synthesis of secondary amines from primary amines has been achieved. Importantly, a practical application to the synthesis of antiparkinsonian agent piribedil has been demonstrated.
- Huang, Hai,Kang, Jun Yong
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supporting information
p. 544 - 547
(2017/02/10)
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- Radical Hydrodehalogenation of Aryl Bromides and Chlorides with Sodium Hydride and 1,4-Dioxane
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A practical method for radical chain reduction of various aryl bromides and chlorides is introduced. The thermal process uses NaH and 1,4-dioxane as reagents and 1,10-phenanthroline as an initiator. Hydrodehalogenation can be combined with typical cyclization reactions, proving the nature of the radical mechanism. These chain reactions proceed by electron catalysis. DFT calculations and mechanistic studies support the suggested mechanism.
- Hokamp, Tobias,Dewanji, Abhishek,Lübbesmeyer, Maximilian,Mück-Lichtenfeld, Christian,Würthwein, Ernst-Ulrich,Studer, Armido
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supporting information
p. 13275 - 13278
(2017/10/09)
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- A General Copper Catalyst for Photoredox Transformations of Organic Halides
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A broadly applicable copper catalyst for photoredox transformations of organic halides is reported. Upon visible light irradiation in the presence of catalytic amounts of [(DPEphos)(bcp)Cu]PF6 and an amine, a range of unactivated aryl and alkyl halides were shown to be smoothly activated through a rare Cu(I)/Cu(I)?/Cu(0) catalytic cycle. This complex efficiently catalyzes a series of radical processes, including reductions, cyclizations, and direct arylation of arenes.
- Michelet, Bastien,Deldaele, Christopher,Kajouj, Sofia,Moucheron, Cécile,Evano, Gwilherm
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supporting information
p. 3576 - 3579
(2017/07/17)
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- N-Methylanilines as Simple and Efficient Promoters for Radical-Type Cross-Coupling Reactions of Aryl Iodides
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Activation of the carbon–halogen bonds in aryl halides is a key step in transition-metal-free cross-coupling reactions. In this paper, a new and efficient radical initiation system for the activation of iodoarenes to produce aryl radicals was discovered, which employs the combination of N-methylanilines and tBuOK. This radical initiation system is robust and versatile, enabling various types of aryl-radical-related reactions.
- Yang, Huan,Zhang, Li,Jiao, Lei
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supporting information
p. 65 - 69
(2017/01/09)
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- From insertion to multicomponent coupling: Temperature dependent reactions of arynes with aliphatic alcohols
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The temperature dependent selectivity switch in the reaction of arynes with aliphatic alcohols in THF has been reported. At -20°C, arynes smoothly insert into the O-H bond of alcohols to form alkyl aryl ethers. Interestingly, at 60°C, a highly selective multicomponent coupling occurs with the solvent THF acting as the nucleophilic trigger affording (4-(alkoxy)butoxy)arenes.
- Thangaraj, Manikandan,Bhojgude, Sachin Suresh,Mane, Manoj V.,Biju, Akkattu T.
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supporting information
p. 1665 - 1668
(2016/01/30)
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- Masked N-Heterocyclic Carbene-Catalyzed Alkylation of Phenols with Organic Carbonates
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An easily prepared masked N-heterocyclic carbene, 1,3-dimethylimidazolium-2-carboxylate (DMI-CO2), was investigated as a “green” and inexpensive organocatalyst for the alkylation of phenols. The process made use of various low-toxicity and renewable alkylating agents, such as dimethyl- and diethyl carbonate, in a focused microwave reactor. DMI-CO2 was found to be a very active catalyst and excellent yields of a range of aryl alkyl ethers were obtained under relatively benign conditions. The observed difference in the conversion behavior of phenol methylation, in the presence of either the carbene or 1,8-diazabicycloundec-7-ene (DBU) catalyst, was rationalized on the basis of mechanistic investigations. The primary mode of action for the N-heterocyclic carbene is nucleophilic catalysis. Activation of the dialkyl carbonate electrophile results in concomitant evolution of an organo-soluble alkoxide, which deprotonates the phenolic starting material. In contrast, DBU is initially protonated by the phenol and thus consumed. Subsequent regeneration and participation in nucleophilic catalysis only becomes significant after some phenolate alkylation occurs.
- Lui, Matthew Y.,Yuen, Alexander K. L.,Masters, Anthony F.,Maschmeyer, Thomas
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p. 2312 - 2316
(2016/10/24)
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- Nickel-catalyzed C-N bond reduction of aromatic and benzylic quaternary ammonium triflates
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A nickel-catalyzed, efficient C-N bond reduction of aromatic and benzylic ammonium triflates has been developed using sodium isopropoxide as a reducing agent. The high efficiency, mild conditions, and good compatibility with various substituents made this method an effective supplement to the current catalytic hydrogenation reactions. Combining this reductive deamination reaction with directed aromatic functionalization reactions, a powerful strategy for regioselective functionalization of arenes was demonstrated using dialkylamine groups as traceless directing groups.
- Yi, Yuan-Qiu-Qiang,Yang, Wen-Cheng,Zhai, Dan-Dan,Zhang, Xiang-Yu,Li, Shuai-Qi,Guan, Bing-Tao
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supporting information
p. 10894 - 10897
(2016/09/09)
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- Light-Mediated Reductive Debromination of Unactivated Alkyl and Aryl Bromides
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Cleavage of carbon-halogen bonds via either single-electron reduction or atom transfer is a powerful transformation in the construction of complex molecules. In particular, mild, selective hydrodehalogenations provide an excellent follow-up to the application of halogen atoms as directing groups or the utilization of atom transfer radical addition (ATRA) chemistry for the production of hydrocarbons. Here we combine the mechanistic properties of photoredox catalysis and silane-mediated atom transfer chemistry to accomplish the hydrodebromination of carbon-bromide bonds. The resulting method is performed under visible light irradiation in an open vessel and is capable of the efficient reduction of a variety of unactivated alkyl and aryl substrates.
- Devery, James J.,Nguyen, John D.,Dai, Chunhui,Stephenson, Corey R. J.
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p. 5962 - 5967
(2016/09/09)
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- Selective hydrogenolysis of phenols and phenyl ethers to arenes through direct C-O cleavage over ruthenium-tungsten bifunctional catalysts
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Direct hydrogenolysis of the aromatic Csp2-O bonds in both phenols and phenyl ethers to form arenes selectively is a core enabling technology that can expand greatly the scope of chemical manufacture from biomass. However, conventional hydrogenolysis of phenols typically led to aromatic ring saturation instead of the cleavage of the Csp2-O bonds. Herein, we report a recyclable Ru-WOx bifunctional catalyst that showed high catalytic activities for the hydrogenolysis of a wide range of phenols and phenyl ethers, including dimeric lignin model compounds and the primitive phenols separated from pyrolysis lignin, to form arenes selectively in water. Preliminary mechanistic studies supported that the reactions occurred via a direct cleavage of the Csp2-O bonds and the concerted effects of the hydrogenating Ru sites and the Lewis acidic W sites are the key to such an unusual reactivity.
- Huang, Yao-Bing,Yan, Long,Chen, Meng-Yuan,Guo, Qing-Xiang,Fu, Yao
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p. 3010 - 3017
(2015/05/27)
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- Air-stable palladium(0) phosphine sulfide catalysts for Ullmann-type C-N and C-O coupling reactions
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This paper describes an efficient procedure for palladium(0)-catalyzed N-arylation and O-arylation of aryl halides by Ullmann-type cross coupling reaction under mild reaction conditions in a short reaction time. Two phosphine sulphide ligands and their corresponding Pd(0) complexes namely [Pd(p2S2)(dba)] and [Pd(pp3S4)(dba)], were synthesized, where p2S2 is 1,2-bis(diphenylphosphino)ethane disulfide, pp3S4 is tris[2-(diphenylphosphino)ethyl]phosphine tetrasulfide and dba is dibenzylideneacetone. Optimal reaction conditions were determined for the arylation reactions using iodobenzene and benzimidazole by varying temperature, solvent, base and catalyst loading. The cross coupling reactions were carried out taking iodobenzenes/bromobenzenes and a wide variety of substituted aryl amines/phenols/alcohols with different steric and electronic properties to afford the desired N-aryl amines/diaryl ethers/alkyl aryl ethers in good to excellent yield (70-94%).
- Majumder, Arpi,Gupta, Ragini,Mandal, Mrinmay,Babu, Madhu,Chakraborty, Debashis
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