- Heterocyclization Approach for Electrooxidative Coupling of Functional Primary Alkylamines with Aromatics
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A new approach for electrooxidative coupling of aromatic compounds and primary alkylamines bearing a functional group such as a hydroxyl group and an amino group was developed. The key to the success of the transformation is heterocyclization of functional primary alkylamines. Treatment of primary alkylamines bearing a functional group with nitriles or their equivalents gives the corresponding heterocycles. The electrochemical oxidation of aromatic substrates in the presence of the heterocycles followed by chemical reaction under nonoxidative conditions gave the desired coupling products.
- Morofuji, Tatsuya,Shimizu, Akihiro,Yoshida, Jun-Ichi
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- Suzuki-type cross-coupling reaction of pentavalent triarylantimony diacetates with arylboronic acids without a base
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Novel base-free Suzuki-type cross-coupling reaction by the use of triarylantimony diacetates and arylboronic acids in the presence of Pd(PPh3)4 catalyst led to the formation of biaryl derivatives in moderate to excellent yields. The reaction is applicable to a variety of arylboronic acids bearing base-sensitive functional groups.
- Yasuike, Shuji,Qin, Weiwei,Sugawara, Yoshiyuki,Kurita, Jyoji
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- Synthesis of 3-(Arylsulfonyl)benzothiophenes and Benzoselenophenes via TBHP-Initiated Radical Cyclization of 2-Alkynylthioanisoles or -selenoanisoles with Sulfinic Acids
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tert-Butyl hydroperoxide-initiated radical cyclization of 2-alkynylthioanisoles or -selenoanisoles with sulfinic acids has been developed. This reaction is applicable to a wide substrate scope via one C(sp3)-S(Se) bond cleavage and two C(sp2)-S(Se) bond formation, leading to the synthesis of 3-(arylsulfonyl)benzothiophenes or -benzoselenophenes under mild conditions.
- Xu, Jian,Yu, Xiaoxia,Yan, Jianxiang,Song, Qiuling
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- Room-temperature Pd/Ag direct arylation enabled by a radical pathway
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Direct arylation is an appealing method for preparing π-conjugated materials, avoiding the prefunctionalization required for traditional cross-coupling methods. A major effort in organic electronic materials development is improving the environmental and economic impact of production; direct arylation polymerization (DArP) is an effective method to achieve these goals. Room-temperature polymerization would further improve the cost and energy efficiencies required to prepare these materials. Reported herein is new mechanistic work studying the underlying mechanism of room temperature direct arylation between iodobenzene and indole. Results indicate that room-temperature, Pd/Ag-catalyzed direct arylation systems are radical-mediated. This is in contrast to the commonly proposed two-electron mechanisms for direct arylation and appears to extend to other substrates such as benzo[b]thiophene and pentafluorobenzene.
- Luscombe, Christine K.,Mayhugh, Amy L.
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- Para-coupling of phenols with C2/C3-substituted benzothiophene S-oxides
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C2 and C3 substituted benzothiophenes are common structures in medicinal and materials chemistry. The cross-coupling of phenols with benzothiophenes is a useful route towards these important molecules. In this report we reveal an efficient C–H/C–H-type cross-coupling of benzothiophenes, activated as their S-oxides, with phenols to give C2/C3 arylated benzothiophenes. Whereas previous reports describe cross-coupling at the ortho-position between phenols and sulfoxides, this procedure allows para-functionalization of phenols that typically have their ortho positions blocked.
- He, Zhen,Biremond, Tony,Perry, Gregory J.P.,Procter, David J.
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- A simple phenylation of heteroaromatic compounds using diphenyliodonium triflate
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In this study a novelmethod for direct synthesis of 2-phenyl heteroaromatic arenes was successfully developed. The title compounds were synthesized by reaction of heteroaromatic compoundswith diphenylene iodonium trifluoromethanesulfonate in the presence of 5 mol% Pd(OAc)2 under mild reaction conditions (THF, 60 °C, 24 h). The proposed reaction mechanism was studied by HPLC. Springer Science+Business Media B.V. 2011.
- Yang, Qi,Chang, Jiao,Wu, Qun,Zhang, Bianxiang
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- Regioselective Direct C2 Arylation of Indole, Benzothiophene and Benzofuran: Utilization of Reusable Pd NPs and NHC-Pd@MNPs Catalyst for C–H Activation Reaction
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Abstract: A regioselective C2 arylation of indoles, benzothiophene and benzofuran without directing group has been accomplished using economically cheap Pd NPs and NHC-Pd@MNPs catalyst. The reusable catalyst is efficiently employed to access C2 arylated heterocycles in good to excellent yield. The reusability of the catalyst is studied up to five cycles and a gram-scale synthesis has been achieved. The reaction mechanism is well supported by control experiments and literature precedents. Grapic Abstract: [Figure not available: see fulltext.]
- Hegde, Rajeev V.,Ong, Tiow-Gan,Ambre, Ram,Jadhav, Arvind H.,Patil, Siddappa A.,Dateer, Ramesh B.
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- Annulative π-Extension (APEX) of Heteroarenes with Dibenzosiloles and Dibenzogermoles by Palladium/o-Chloranil Catalysis
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Annulative π-extension (APEX) reactions of heteroarenes are described herein. A catalytic system comprising a cationic palladium species and o-chloranil using dimethyldibenzosiloles as π-extending agents enabled the extension of the π-system of benzo[b]thiophenes. π-Extended dibenzofurans and carbazoles could also be obtained from benzofuran and N-tosylindole, respectively, with dimethyldibenzogermole as a germanium-based π-extending agent. Mechanistic investigations indicated two possible reaction pathways involving carbopalladation-based double C-H arylation of benzothiophene or formal cycloaddition/oxidation cascades.
- Ozaki, Kyohei,Matsuoka, Wataru,Ito, Hideto,Itami, Kenichiro
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- Asymmetric Cyclizative Dimerization of (ortho-Alkynyl Phenyl) (Methoxymethyl) Sulfides with Palladium(II) Bisoxazoline Catalyst
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The first example of an asymmetric cyclization–dimerization of (ortho-alkynyl phenyl) (methoxymethyl) sulfides with a palladium(II) bisoxazoline (box) catalyst has been developed. The box ligand enhances the alkynophilicity of benzothienyl palladium(II) intermediate A and thus promotes coordination of the second alkyne substrate, leading to the dimerization. The characteristic properties of the box ligand were supported by density functional theory (DFT) calculations of the intermediate. Axially chiral bibenzothiophenes were obtained in good yields with good enantioselectivities.
- Peng, Cheng,Kusakabe, Taichi,Kikkawa, Shoko,Mochida, Tomoyuki,Azumaya, Isao,Dhage, Yogesh Daulat,Takahashi, Keisuke,Sasai, Hiroaki,Kato, Keisuke
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- An efficient tandem elimination-cyclization-desulfitative arylation of 2-(gem-dibromovinyl)phenols(thiophenols) with sodium arylsulfinates
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An efficient tandem elimination-cyclization-desulfitative arylation of 2-(gem-dibromovinyl)phenols(thiophenols) with sodium arylsulfinates has been developed. In the presence of TBAF-PdCl2-Cu(OAc)2-NEt 3, the reactions gen
- Chen, Wei,Li, Pinhua,Miao, Tao,Meng, Ling-Guo,Wang, Lei
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- Infrared Irradiation-Assisted Solvent-Free Pd-Catalyzed (Hetero)aryl-aryl Coupling via C?H Bond Activation
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The increasing attention towards environmentally friendly synthetic protocols has boosted studies directed to the development of green and sustainable methods for direct C?H bond arylation of (hetero)arenes. In this context, here the infrared (IR) irradia
- Albano, Gianluigi,Decandia, Gianfranco,Capozzi, Maria Annunziata M.,Zappimbulso, Nicola,Punzi, Angela,Farinola, Gianluca M.
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- A family of low molecular-weight, organic catalysts for reductive C-C bond formation
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Hydrazines form a new family of low molecular-weight reducing agents for diazonium salts. Using only small amounts of hydrazine catalyst, the coupling of diazonium salts to a variety of reactive partners has been achieved, without the requirement for either metal adjuvants or irradiation with visible or ultraviolet light. The generality of the concept proposed herein as well as its advantages in the preparative scale is outlined and discussed.
- Shaaban, Saad,Jolit, Ana?s,Petkova, Desislava,Maulide, Nuno
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- Palladium-Catalyzed Arylation of Azole Compounds with Aryl Halides in the Presence of Alkali Metal Carbonates and the Use of Copper Iodide in the Reaction
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The reactions of iodobenzene with azole compounds, 1,2-disubstituted imidazoles and 2-substituted oxazoles and thiazoles, were examined in the presence of catalytic amounts of Pd(OAc)2 and PPh3 in DMF using alkali metal carbonates as bases. It was found that the coupling products, 5-arylazoles, could be selectively produced in good yields by using CS2CO3. In the case that their 2-position is unsubstituted, the site could also be arylated. In reactions using bromobenzene in place of iodobenzene, K2CO3 was also as effective as Cs2CO3- The addition of a stoichiometric amount of Cul appeared to specifically promote the reactions of thiazoles as well as those of thiophene derivatives. The reactions of 2-unsubstituted azole compounds with aryl iodides could be mediated by Cul to some extent without using the palladium species to give 2-arylazoles.
- Pivsa-Art, Sommai,Satoh, Tetsuya,Kawamura, Yoshiki,Miura, Masahiro,Nomura, Masakatsu
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- Benzofurans prepared by C-H bond functionalization with acylsilanes
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(Chemical Equation Presented) Instant carbenes - that's hot: The thermal 1,2-Brook rearrangement of acylsilanes generates siloxycarbene intermediates that can undergo intramolecular C-H bond insertion to provide benzofuran derivatives. This metal-free tan
- Shen, Zengming,Dong, Vy M.
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- Palladium bis(2,2,6,6-tetramethyl-3,5-heptanedionate): an efficient catalyst for regioselective C-2 arylation of heterocycles
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Palladium bis(2,2,6,6-tetramethyl-3,5-heptanedionate), a structurally well defined O-containing transition metal complex is reported as an efficient catalyst for regioselective direct C-2 arylation of heterocycles with aryl halides. The present protocol is applicable to a wide variety of heterocycles providing good to excellent yields of products.
- Nandurkar, Nitin S.,Bhanushali, Mayur J.,Bhor, Malhari D.,Bhanage, Bhalchandra M.
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- Metalated Porous Phenanthroline-Based Polymers as Efficient Heterogeneous Catalysts for Regioselective C?H Activation of Heteroarenes
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Direct C?H bond activation of heterocycles as a step-economical and environmentally friendly approach to build the heterobiaryls motifs is highly attractive, but it still has a challenge to design and prepare a cheap and regioselective heterogeneous catal
- Tang, Yongquan,Dai, Zhifeng,Wang, Sai,Chen, Fang,Meng, Xiangju,Xiao, Feng-Shou
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p. 2469 - 2474
(2021/08/06)
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- Synthesis of 2-Substituted Benzothio(seleno)phenes and Indoles via Ag-Catalyzed Cyclization/Demethylation of 2-Alkynylthio(seleno)anisoles and 2-Alkynyldimethylanilines
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An Ag-catalyzed cyclization/demethylation of 2-alkynylthio(seleno)anisoles and 2-alkynyldimethylanilines is described and applied for the construction of valuable benzothio(seleno)phenes as well as indoles. Various 2-substituted benzothio(seleno)phenes and indoles were obtained in good to excellent yields under mild reaction conditions with low catalyst loading. An application of this new method is also exemplified with a concise synthesis of a bioactive molecule precursor. Furthermore, a conceivable reaction mechanism is proposed with supports from isotope-exchange experiments.
- Cai, Tao,Feng, Chengjie,Shen, Fangqi,Bian, Kejun,Wu, Chunlei,Shen, Runpu,Gao, Yuzhen
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p. 653 - 656
(2020/12/23)
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- Dephosphinylative [4 + 2] Benzannulation of Phosphinyl Ynamines: Application to the Modular Synthesis of Polycyclic Aromatic Amines
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A series of 9-amino-10-halophenanthrenes were synthesized through a one-pot process, including dephosphinylative Sonogashira–Hagihara coupling of 2-bromobiphenyls with air-stable phosphinyl ynamines, followed by halonium-promoted [4 + 2] benzannulation of the resulting 2-(aminoethynyl)biphenyls. Nonsubstituted and methyl-substituted 2-bromobiphenyls rapidly underwent the Sonogashira–Hagihara aminoethynylation and the halogenative Friedel–Crafts benzannulation to provide the corresponding amino(halo)phenanthrenes in high yields, while electron-sufficient and -deficient substrates did slowly undergo the former and the latter to result in low yields, respectively. This protocol worked well for the syntheses of highly π-extended aminophenanthrenes and aminobenzonaphthothiophenes with different optical properties. Further application of this approach between 2,2″- and 2′,5′-dibromo-p-terphenyls with phosphinyl ynamines led to the regioselective formation of 6,13-diamino-5,12-dihalo- and 5,12-diamino-6,13-dihalo-dibenz[a,h]anthracenes via dual aminoethynylation and [4 + 2] benzannulation. The obtained analogues showed different ultraviolet–visible absorption and photoluminescence spectra with different emission quantum yields in CH2Cl2 solution and the powder state.
- Okuda, Yasuhiro,Fujimoto, Mayo,Akashi, Haruo,Orita, Akihiro
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supporting information
p. 17651 - 17666
(2021/12/13)
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- Iminyl-radicals by electrochemical decarboxylation of α-imino-oxy acids: construction of indole-fused polycyclics
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Iminyl radicals are reactive intermediates that can be used for the construction of various valuable heterocycles. Herein, the electrochemical decarboxylation of α-imino-oxy acids for the generation of iminyl radicals has been accomplished under exogenous-oxidant- and metal-free conditions through the use ofnBu4NBr as a mediator. The resulting iminyl radicals undergo intramolecular cyclization smoothly with the adjacent (hetero)arenes to afford a series of indole-fused polycyclic compounds.
- Wan, Jin-Lin,Cui, Jian-Feng,Zhong, Wei-Qiang,Huang, Jing-Mei
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supporting information
p. 10242 - 10245
(2021/10/12)
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- Trithiocarbonate Anion as a Sulfur Source for the Synthesis of 2,5-Disubstituted Thiophenes and 2-Substituted Benzo[ b]thiophenes
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The trithiocarbonate anion (CS32-) was generated in situ from CS2 and KOH in dimethyl sulfoxide by a simple method and used as a novel synthetic equivalent of the S2- synthon for the synthesis of 2,5-disubstituted thiophenes from 1,3-butadiynes. Additionally, this system was employed for the metal-free synthesis of 2-substituted benzo[b]thiophenes from 2-haloalkynyl (hetero)arenes. These compounds were obtained from a cheap and readily available sulfur source in moderate to good yields, with good functional group tolerance.
- Paix?o, Douglas B.,Rampon, Daniel S.,Salles, Helena D.,Soares, Eduardo G. O.,Bilheri, Filipe N.,Schneider, Paulo H.
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supporting information
p. 12922 - 12934
(2020/11/26)
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- Nickel-catalyzed and Li-mediated regiospecific C-H arylation of benzothiophenes
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A nickel-based catalytic system for the regiospecific C2-H arylation of benzothiophene has been established. NiCl2(bpy) is used as a catalyst in combination with LiHMDS as a base in dioxane. The catalytic system is applicable to a variety of functionalized benzothiophenes, as well as other heteroarenes including thiophene, benzodithiophene, benzofuran and selenophene in combination with iodo aryl electrophiles. The role of LiHMDS as a uniquely potent base and a postulated mechanism are discussed. The applicability of this system is finally demonstrated for the synthesis of an intermediate of an active pharmaceutical ingredient.
- Canivet, Jér?me,Grousset, Léonie,Hisler, Ga?lle,Mohr, Yorck,Quadrelli, Elsje Alessandra,Roux, Yoann,Wisser, Florian M.
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p. 3155 - 3161
(2020/06/19)
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- C-H Arylation of Thiophenes with Aryl Bromides by a Parts-per-Million Loading of a Palladium NNC-Pincer Complex
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A palladium NNC-pincer complex efficiently catalyzed the direct arylation of thiophene derivatives with extremely low palladium loadings of the order of parts per million. Thus, the reaction of various thiophenes with aryl bromides in the presence of 25-100 mol ppm of chlorido[(2-phenyl-κ- C 2)-9-phenyl-1,10-phenanthroline-κ 2- N, N ′]palladium(II) NNC-pincer complex, K 2CO 3, and pivalic acid in N, N -dimethyl acetamide afforded the corresponding 2- or 5-arylated thiophenes in good to excellent yields. A combination of the present C-H arylation and Hiyama coupling with the same NNC-pincer complex provides an efficient synthesis of unsymmetrical 2,5-thiophenes with catalyst loadings at mol ppm levels.
- Purta, Anggi Eka,Ichii, Shun,Tazawa, Aya,Uozumi, Yasuhiro
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supporting information
p. 1634 - 1638
(2020/08/28)
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- A Convoluted Polyvinylpyridine-Palladium Catalyst for Suzuki-Miyaura Coupling and C?H Arylation
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The development of highly active and reusable supported catalysts for Suzuki-Miyaura coupling and catalytic C?H arylation is important for fundamental and applied chemistry, with these reactions being used to produce medical compounds and functional materials. Herein, we found that a mesoporous composite made of a linear poly(4-vinylpyridine) and tetrachloropalladate acted as a dual-mode catalyst for a variety of cross-coupling reactions, with both Pd nanoparticles and a Pd complex catalyst being observed under different conditions. The polyvinylpyridine-palladium composite 1 was readily prepared via the molecular convolution of poly(4-vinylpyridine) and sodium tetrachloropalladate to provide a hardly soluble polymer-metal composite. The Suzuki-Miyaura coupling and the C?H arylation of aryl chlorides and bromides with arylboronic acids, thiophenes, furans, benzene, and anisole proceeded in the presence of 0.004 mol% (40 mol ppm) to 1 mol% Pd of 1 to afford the corresponding coupling products in high yields. Furthermore, the catalyst was reused without an appreciable loss of activity. Pharmaceutical compounds and functional materials were synthesized via the coupling reactions. N2 gas adsorption/desorption analysis indicated that the catalyst had a mesoporous nature, which played a crucial role in the catalysis. In the Suzuki-Miyaura couplings, in situ generated palladium nanoparticles in the polymer matrix were catalytically active, while a polymeric Pd(II) complex was crucial in the C?H arylations. These catalytic species were investigated via XAFS, XPS, far-infrared absorption, and Raman spectroscopies, as well as DFT calculations. (Figure presented.).
- Ohno, Aya,Sato, Takuma,Mase, Toshiaki,Uozumi, Yasuhiro,Yamada, Yoichi M. A.
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supporting information
p. 4687 - 4698
(2020/09/07)
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- σ-Bond initiated generation of aryl radicals from aryl diazonium salts
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σ-Bond nucleophiles and molecular oxygen transform aryl diazonium salts into aryl radicals. Experimental and computational studies show that Hantzsch esters transfer hydride to aryl diazonium species, and that oxygen initiates radical fragmentation of the diazene intermediate to produce aryl radicals. The operational simplicity of this addition-fragmentation process for the generation of aryl radicals, by a polar-radical crossover mechanism, has been illustrated in a variety of bond-forming reactions.
- Chan, Bun,McErlean, Christopher S. P.,Nashar, Philippe E.,Tatunashvili, Elene
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supporting information
p. 1812 - 1819
(2020/03/17)
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- Transition-Metal-Free Oxidative Cross-Coupling of Tetraarylborates to Biaryls Using Organic Oxidants
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Readily prepared tetraarylborates undergo selective (cross)-coupling through oxidation with Bobbitt's salt to give symmetric and unsymmetric biaryls. The organic oxoammonium salt can be used either as a stoichiometric oxidant or as a catalyst in combination with in situ generated NO2 and molecular oxygen as the terminal oxidant. For selected cases, oxidative coupling is also possible with NO2/O2 without any additional nitroxide-based cocatalyst. Transition-metal-free catalytic oxidative ligand cross-coupling of tetraarylborates is unprecedented and the introduced method provides access to various biaryl and heterobiaryl systems.
- Gerleve, Carolin,Studer, Armido
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supporting information
p. 15468 - 15473
(2020/05/06)
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- Highly Selective and Divergent Acyl and Aryl Cross-Couplings of Amides via Ir-Catalyzed C-H Borylation/N-C(O) Activation
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Herein, we demonstrate that amides can be readily coupled with nonactivated arenes via sequential Ir-catalyzed C-H borylation/N-C(O) activation. This methodology provides facile access to biaryl ketones and biaryls by the sterically controlled Ir-catalyzed C-H borylation and divergent acyl and decarbonylative amide N-C(O) and C-C activation. The methodology diverts the traditional acylation and arylation regioselectivity, allowing us to directly utilize readily available arenes and amides to produce valuable ketone and biaryl motifs.
- Gao, Pengcheng,Szostak, Michal
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supporting information
p. 6010 - 6015
(2020/07/30)
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- Transition-Metal-Free Synthesis of Heterobiaryls through 1,2-Migration of Boronate Complex
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The synthesis of a diverse range of heterobiaryls has been achieved by a transition-metal-free sp2–sp2 cross-coupling strategy using lithiated heterocycle, aryl or heteroaryl boronic ester and an electrophilic halogen source. The construction of heterobiaryls was carried out through electrophilic activation of the aryl–heteroaryl boronate complex, which triggered 1,2-migration from boron to the carbon atom. Subsequent oxidation of the intermediate boronic ester afforded heterobiaryls in good yield. A comprehensive 11B NMR study has been conducted to support the mechanism. The cross coupling between two nucleophilic cross coupling partners without transition metals reveals a reliable manifold to procure heterobiaryls in good yields. Various heterocycles like furan, thiophene, benzofuran, benzothiophene, and indole are well tolerated. Finally, we have successfully demonstrated the gram scale synthesis of the intermediates for an anticancer drug and OLED material using our methodology.
- Paul, Swagata,Das, Kanak Kanti,Manna, Samir,Panda, Santanu
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supporting information
p. 1922 - 1927
(2020/02/04)
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- Copper-catalysed three-component carboiodination of arynes: Expeditious synthesis of: O -alkynyl aryl iodides
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A copper-catalysed three-component iodoalkynylation reaction of arynes for the expeditious and versatile synthesis of o-alkynyl aryl iodides has been developed. Mechanism research shows that the reaction goes through two steps enabled by copper catalysis: the formation of 1-iodo-2-arylacetylene and the insertion of the aryne into a C(sp)-I bond.
- Cao, Wenxuan,Niu, Sheng-Li,Shuai, Li,Xiao, Qing
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p. 972 - 975
(2020/02/03)
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- Synthesis of [1]benzothiopheno[2,3-b][1]benzothiophene derivatives through iodine-mediated sulfuration reaction of 1,1-diarylethylenes
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Acceleration of the reaction for the synthesis of [1]benzothiopheno[2,3-b][1]benzothiophenes (BTBTs) from 1,1-diarylethylenes was accomplished by the addition of molecular iodine. Postulated intermediates 3-arylbenzo[b]thiophenes were also selectively prepared by simply changing the amount of iodine and the reaction time.
- Sakai, Shuta,Sato, Kazuki,Yoshida, Kazuhiro
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- B(C6F5)3-Catalyzed cyclization of alkynes: direct synthesis of 3-silyl heterocyclic compounds
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An efficient one-pot strategy for easy access to 3-silyl heterocyclic compounds was developedviaa B(C6F5)3-catalyzed cycloaddition reaction ofo-(1-alkynyl)(thio)anisoles oro-(1-alkynyl)-N-methylaniline. In this reaction, benzenethiophene, benzofuran or indole skeletons could be constructed by an intermolecular cyclization with diphenylsilane. This protocol elicited moderate-to-good yields with metal-free reaction systems.
- Li, Mengxing,Wang, Ting,An, Zhenyu,Yan, Rulong
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supporting information
p. 11953 - 11956
(2020/10/15)
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- Synthesis of Enaminone-Pd(II) Complexes and Their Application in Catalysing Aqueous Suzuki-Miyaura Cross Coupling Reaction
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A series of Pd(II)-enaminone complexes, termed Pd(eao)2, have been synthesized and characterized. The investigation on the catalytic activities of these new Pd(II)-reagents has proved that the Pd(eao)2-1 possesses excellent catalytic activity for the Suzuki- Miyaura cross coupling reactions of aryl bromides/chlorides with aryl/vinyl boronic acids in the environmentally benign media of aqueous PEG400 at low loading (5 mol‰). The superiority of this Pd(II)-reagent to those commercial Pd(II) and Pd(0) catalysts in catalyzing the reactions has been confirmed by parallel experiments. What's more, Pd(eao)2-2 has been found as a practical catalyst for the homo-coupling reactions of aryl boronic acids.
- Fu, Leiqing,Cao, Xiaoji,Wan, Jie-Ping,Liu, Yunyun
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p. 254 - 258
(2020/01/25)
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- Transition-Metal-Free Synthesis of 1,2-Disubstituted Indoles
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Herein, we report a new transition-metal-free robust and cost-effective method for synthesis of 1,2-disubstituted indoles from easily available unactivated (i.e. without EWG, PPh3 or SiR3 groups) tertiary amides. Scope of synthetic applicability of the presented protocol was shown on 23 examples of 1,2-disubstituted indoles with different substitution patterns obtained in good to excellent yields. The reported method turned out to be especially effective for synthesis of N-arylated 2-CF3-indoles. Moreover, this approach can be performed in a one-pot two-step manner directly from commercially available secondary amines. Mechanistic studies showed that acyl transfer might be an important step in the course of the reaction. Viability of the presented approach for benzofurans and benzothiophenes synthesis was also discussed.
- Chesnokov, Gleb A.,Ageshina, Alexandra A.,Topchiy, Maxim A.,Nechaev, Mikhail S.,Asachenko, Andrey F.
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p. 4844 - 4854
(2019/08/01)
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- Method for preparing benzothiophene compounds by silver oxide catalysis method
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The invention provides a method for preparing benzothiophene compounds through a silver oxide catalysis method, and belongs to the technical field of heterocyclic compound preparation. In the presenceof an acidic solvent, the 2-acetenyl diphenyl sulfide a
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Paragraph 0062-0066
(2019/12/02)
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- Highly Efficient Enantioselective Synthesis of Chiral Sulfones by Rh-Catalyzed Asymmetric Hydrogenation
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A highly efficient and enantioselective Rh-(R,R)-f-spiroPhos complex catalyzed hydrogenation of a series of unsaturated sulfones has been developed. With Rh-(R,R)-f-spiroPhos catalyst under mild conditions, not only the asymmetric hydrogenation of both the 3,3-diaryl and exocyclic α,β-unsaturated sulfones was first realized with up to 99.9% ee but also 3-alkyl-3-aryl and benzo[b]thiophene-1,1-dioxides were successfully hydrogenated to the corresponding chiral sulfones with excellent enantioselectivities (up to 99.4% ee) regardless of the steric hindrance, electronic property, and geometry of the substrates. Moreover, this reaction offers a route to (S)-(+)-ar-turmerone as a spice flavor, which is an important synthetic intermediate of pharmaceuticals.
- Yan, Qiaozhi,Xiao, Guiying,Wang, Ying,Zi, Guofu,Zhang, Zhanbin,Hou, Guohua
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supporting information
p. 1749 - 1756
(2019/01/25)
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- Arylation synthesis method for novel five-membered aromatic heterocycle and aromatic-ring five-membered aromatic heterocycle
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The invention belongs to the technical field of organic synthesis and in particular relates to an arylation synthesis method for a five-membered aromatic heterocycle or an aromatic-ring five-memberedaromatic heterocycle under the participation of an arylhydrazine derivative serving as a novel arylation reagent. The method comprises the steps: adding a raw material and aroyl hydrazine into a reactor, and carrying out a reaction at 60-100 DEG C for 8-24h under the condition that an oxidant and a transition metal catalyst are added; after the reaction is ended, carrying out suction filtration, extracting a filtrate by using ethyl acetate, carrying out drying to obtain a crude product of a target compound, and carrying out column chromatography on silica gel to obtain a pure product of the target compound. The arylation synthesis method for the five-membered aromatic heterocycle or the aromatic-ring five-membered aromatic heterocycle is scientific and reasonable and has the advantages such as simplicity and convenience in operation, relatively high yield and simplicity in amplification and purification.
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Paragraph 0112-0115; 0192-0195
(2018/07/07)
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- Ag(I)-C-H Activation Enables Near-Room-Temperature Direct α-Arylation of Benzo[ b]thiophenes
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The first example of near-room-temperature α-arylation of benzo[b]thiophenes is reported. The discovery rests on the observation of a switch in α-/β-regioselectivity at different loadings of Pd2(dba)3·CHCl3 in the coupling between benzo[b]thiophene and 4-iodotoluene. We show that this unprecedented regioselectivity switch is driven by a Ag(I)-mediated C-H activation at the α-C-H position, which becomes the dominant mode of reactivity at low concentrations of Pd. Competition experiments, kinetic studies, KIE, and D/H scrambling experiments have been carried out supporting this mechanism.
- Colletto, Chiara,Panigrahi, Adyasha,Fernández-Casado, Jaime,Larrosa, Igor
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supporting information
p. 9638 - 9643
(2018/07/21)
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- Method for synthesizing benzothiophene derivative by catalysis of dihalogenated aromatics by copper
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The invention discloses a method for synthesizing a benzothiophene derivative by catalysis of dihalogenated aromatics by copper. According to the invention, a catalyst cuprous iodide with a catalysisamount, a ligand 8-hydroxyquinoline, an auxiliary catalyst cesium carbonate and 1-bromine-2-iodobenzene or its derivative, sulfur powder, and phenylacetylene or its derivative are added in a flask andsubjected to a reaction in pure water at certain temperature, after a certain time, vacuum concentration is carried out, and a product is purified through column chromatography. The method has the advantages of novel raw material and simple operation, and can be used for efficiently preparing the benzothiophene derivative. Compared with the prior art, the method has the advantages of mild reaction condition, simple operation, high yield, safety, low cost, and environmental protection.
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Paragraph 0026; 0075; 0076; 0077; 0078
(2018/08/28)
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- Method for synthesizing benzothiophene derivatives from dihaloarene under microwave irradiation under catalysis of copper
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The invention discloses a method for synthesizing benzothiophene derivatives from dihaloarene under microwave irradiation under the catalysis of copper. The method comprises the following steps: adding a catalytic amount of a catalyst copper chloride, a ligand 1,10-phenanthroline (1,10-Phen), a cocatalyst potassium hydroxide, 1-bromo-2-iodobenzene and its derivatives, KSCN (potassium thiocyanate),phenylacetylene and pure water, performing a reaction in a microwave reactor at a certain temperature under a certain power for a certain time, performing reduced pressure concentrating, and performing column chromatography purification on the obtained product. The method disclosed in the invention is a method having novel raw materials, being simple to operate and used for efficiently preparingthe benzothiophene derivatives. Compared with the prior art, the method has an obvious faster reaction speed than convectional heating, and has the advantages of mild reaction conditions, simplicity in operation, high yield, safety, low cost and environmental protection.
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Paragraph 0030; 0079-0084
(2018/09/08)
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- Palladium-Catalyzed Regioselective C-2 Arylation of Benzofurans with N′-Acyl Arylhydrazines
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A novel ligand-free palladium-catalyzed C-2 arylation of benzofurans has been developed using N′-acyl arylhydrazines as the coupling partners and TEMPO as an oxidant. This protocol features a wide functional-group tolerance and highly regioselective products with good to excellent yields.
- Cao, Jun,Chen, Zi-Li,Li, Shu-Min,Zhu, Gao-Feng,Yang, Yuan-Yong,Wang, Cong,Chen, Wen-Zhang,Wang, Jian-Ta,Zhang, Ji-Quan,Tang, Lei
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supporting information
p. 2774 - 2779
(2018/06/21)
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- Synthesis of 2-substituted benzo[: B] thiophenes via gold(i)-NHC-catalyzed cyclization of 2-alkynyl thioanisoles
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Benzo[b]thiophene heterocycles are important components of many important small molecule pharmaceuticals and drug candidates as well as organic semiconducting materials. Many methods have been developed for the construction of a benzo[b]thiophene core via cyclization reaction of alkynes. Although few catalytic reactions were disclosed, most methods rely on stoichiometric activation of alkynes. Here we report an efficient method for the synthesis of 2-substituted benzo[b]thiophenes from 2-alkynyl thioanisoles catalyzed by a gold(i)-IPr hydroxide that is applicable to a wide range of substrates with diverse electronic and steric properties. Additionally, we demonstrate experimentally that the acid additive and its conjugate base are essential to catalyst turnover.
- Dillon, Christopher C.,Keophimphone, Bagieng,Sanchez, Melissa,Kaur, Parveen,Muchalski, Hubert
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supporting information
p. 9279 - 9284
(2019/01/03)
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- Transition-Metal-Free Highly Chemoselective and Stereoselective Reduction with Se/DMF/H2O System
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A novel metal-free reduction system, in which H2Se (or HSe-) produced in situ from Se/DMF/H2O acts as the active reducing species, has been developed. By using water as an inexpensive, safe, and environmentally friendly surrogate as the hydrogen donor, this new reduction system incorporating Se/DMF/H2O displayed high selectivity and good activity in the reduction of α,β-unsaturated ketones and alkynes. Therefore, this reduction system has great potential to be a general and practical reduction methodology in organic transformation.
- Li, Hong-Chen,An, Cui,Wu, Ge,Li, Guo-Xing,Huang, Xiao-Bo,Gao, Wen-Xia,Ding, Jin-Chang,Zhou, Yun-Bing,Liu, Miao-Chang,Wu, Hua-Yue
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supporting information
p. 5573 - 5577
(2018/09/12)
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- Aerobic, Metal-Free, and Catalytic Dehydrogenative Coupling of Heterocycles: En Route to Hedgehog Signaling Pathway Inhibitors
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The nitrosonium ion-catalyzed dehydrogenative coupling of heteroarenes under mild reaction conditions is reported. The developed method utilizes ambient molecular oxygen as a terminal oxidant, and only water is produced as byproduct. Dehydrogenative coupl
- Bering, Luis,Paulussen, Felix M.,Antonchick, Andrey P.
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supporting information
p. 1978 - 1981
(2018/04/16)
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- SINGLE-STEP SYNTHESIS METHOD OF ARYL THIOL AND APPLICATION THEREOF
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The present invention relates to a single-step synthesis method of aryl thiol, and more specifically, to a method of synthesizing aryl thiol in a single-step by making aryl halide react with alkane dithiol in the presence of a transition metal catalyst. According to the present invention, a single-step synthesis method using the transition metal catalyst, the synthesis method which is capable of synthesizing aryl thiol from aryl halide at a high yield, can be provided. Various aryl halides may be applied to the synthesis method. Further, the synthesis method has advantages that an easily usable reagent may be used, operations are simple, and reactions can be performed under mild conditions. In addition, the synthesized aryl thiol may be used in the synthesis of advanced molecules such as diaryl sulfides and benzothiophenes.COPYRIGHT KIPO 2017
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Paragraph 0032; 0033; 0094; 0096; 0097; 0115
(2017/09/02)
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- Extended Study of Visible-Light-Induced Photocatalytic [4 + 2] Benzannulation: Synthesis of Polycyclic (Hetero)Aromatics
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Herein we report an extended study of [4 + 2] benzannulation reactions of 2-(hetero)aryl-substituted anilines with alkynes by visible light photocatalysis. The method requires the use of tBuONO as a diazotizing agent and 0.3 mol % of fac-Ir(ppy)3 as a photocatalyst at room temperature. The reaction proceeded in a chemo- and regioselective manner with high functional group tolerance under mild conditions allowing the preparation of a wide variety of polycyclic (hetero)aromatic compounds, including phenanthrenes, in moderate to high yields. This procedure is amenable to gram-scale synthesis of 9-phenylphenanthrene.
- Chatterjee, Tanmay,Lee, Da Seul,Cho, Eun Jin
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p. 4369 - 4378
(2017/04/28)
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- N-Heterocyclic carbene-Pd(II)-1-methylimidazole complex catalyzed C[sbnd]H bond arylation of (benzo)thiophenes with aryl chlorides
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NHC-Pd(II)-Im complex showed efficient catalytic activity toward the direct C[sbnd]H bond arylation of (benzo)thiophenes with the challenging aryl chlorides. Under the suitable conditions, all reactions proceeded smoothly to give the desired C[sbnd]H bond
- Yin, Shun-Chao,Zhou, Quan,He, Qian-Wei,Li, Shu-Wan,Qian, Peng-Cheng,Shao, Li-Xiong
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p. 427 - 431
(2017/01/13)
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- Arylation method of thiophene compounds
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The invention provides an arylation method of thiophene compounds. The thiophene compounds are benzothiophene or thiophene, and the benzothiophene represented by formula (1) or thiophene represented by formula (2) and aryl chloride represented by formula
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Paragraph 0036; 0037; 0038; 0039; 0040; 0041; 0042; 0043
(2017/08/28)
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- Iridium-Catalyzed Asymmetric Hydrogenation of Benzo[b]thiophene 1,1-Dioxides
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An efficient iridium-catalyzed asymmetric hydrogenation of substituted benzothiophene 1,1-dioxides is described. The use of iridium complexes with chiral pyridyl phosphinite ligands provides access to highly enantiomerically enriched sulfones with substituents at the 2- and 3-position. Sulfones of this type are of interest as core structures of agrochemicals and pharmaceuticals. Moreover, they can be further reduced to chiral 2,3-dihydrobenzothiophenes.
- Tosatti, Paolo,Pfaltz, Andreas
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supporting information
p. 4579 - 4582
(2017/04/11)
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- Synthesis of 2-substituted benzo[b]thiophene via a Pd-catalyzed coupling of 2-iodothiophenol with phenylacetylene
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A Pd(ii)-catalyzed Sonogashira type cross-coupling reaction between 2-iodothiophenol and phenylacetylene has been developed. A series of 2-substituted benzo[b]thiophenes were obtained in moderate to good yield (up to 87%). The application of this method was demonstrated by the synthesis of 2-(4-(tert-butyl)phenyl)benzo[b]thiophene 1,1-dioxide and (4-methoxyphenyl)(2-(4-methoxyphenyl)benzo[b]thiophen-3-yl)methanone, which exhibit a fluorescence quantum yield of up to 1 and can be used as a cannabinoid receptor ligand, respectively.
- Chen, Jingwen,Xiang, Haifeng,Yang, Li,Zhou, Xiangge
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p. 7753 - 7757
(2017/02/05)
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- Bulky α-diimine palladium complexes: Highly efficient for direct C-H bond arylation of heteroarenes under aerobic conditions
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Through the strategy to enhance the bulkiness on both the backbone and the N-aryl moieties, we designed and synthesized a type of bulky α-diimine palladium complex (i.e., {[Ar-NC(R)-C(R)N-Ar]PdCl2, (Ar = 2-benzhydryl-4,6-dimethylphenyl)}, C1, R = H; C2, R = An; C3, R = Ph). The structures of these palladium complexes were well characterized, while C1 and C3 were further characterized by X-ray diffraction. The catalytic performances of the precatalysts were screened for direct C-H bond arylation of heteroarenes. The bidentate N,N-palladium complex C3 with both a backbone and N-aryl bulkiness was found to be a highly efficient precatalyst under aerobic conditions. With a low palladium loading of 0.5-0.1 mol%, a variety of heteroarenes with challenging bulky steric aryl bromides as well as heteroaryl bromides are all applicable for this cross-coupling reaction.
- Ouyang, Jia-Sheng,Li, Yan-Fang,Shen, Dong-Sheng,Ke, Zhuofeng,Liu, Feng-Shou
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p. 14919 - 14927
(2016/10/11)
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- A Pincer Ruthenium Complex for Regioselective C-H Silylation of Heteroarenes
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A pincer Ru(II) catalyst for the highly efficient undirected silylation of O- and S-heteroarenes with (TMSO)2MeSiH and Et3SiH is described, producing heteroarylsilanes with exclusive C2-regioselectivity, good functional-group tolerance, and high turnover numbers (up to 1960). The synthetic utility of the silylated products is demonstrated by Pd-catalyzed Hiyama-Denmark cross-coupling under mild conditions. One-pot, two-step silylation and coupling procedures have been also developed.
- Fang, Huaquan,Guo, Le,Zhang, Yuxuan,Yao, Wubing,Huang, Zheng
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supporting information
p. 5624 - 5627
(2016/11/17)
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- Pd-catalyzed Suzuki–Miyaura cross-coupling of [Ph2SR][OTf] with arylboronic acids
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The Pd-catalyzed Suzuki–Miyaura cross-coupling of alkyl- and fluoroalkyl(diphenyl)sulfonium triflates with arylboronic acids was compared. The fluorine substitution on the alkyl groups of [Ph2SR][OTf] had a big influence on the reaction. Perfluoroalkyl(diphenyl)sulfonium triflates (2b–d) were unsuccessful participants in the Pd-catalyzed phenylation of arylboronic acid under the standard conditions because of the strong electronegativity of the long-chain perfluoroalkyl groups, which underwent S[sbnd]Rfnbond cleavage instead. Polyfluoroalkyl(diphenyl)sulfonium triflates (2f–h) reacted with arylboronic acid to afford the phenylation product in very low yields due to the tendency of deprotonation and β-F elimination of the sulfonium salts. Eventually, (2,2,2-trifluoroethyl)diphenylsulfonium triflate (2e), methyl- or ethyl(diphenyl)sulfonium triflate (2i or 2j), and triphenylsulfonium triflate (2m) were found to be more effective reagents than other tested phenylsulfounium salts for Pd-catalyzed phenylation, which provided much higher yields of the desired products under mild conditions.
- Wang, Xiao-Yan,Song, Hai-Xia,Wang, Shi-Meng,Yang, Jing,Qin, Hua-Li,Jiang, Xin,Zhang, Cheng-Pan
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p. 7606 - 7612
(2016/11/11)
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- Three-component 2-aryl substituted benzothiophene formation under transition-metal free conditions
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A base-mediated 2-aryl substituted benzothiophene formation from 2-bromobenzene aldehydes, benzylic esters and elemental sulfur under transition-metal-free conditions is described. Various 2-aryl substituted benzothiophene were efficiently obtained under mild conditions.
- Jiang, Pengcheng,Che, Xingzong,Liao, Yunfeng,Huang, Huawen,Deng, Guo-Jun
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p. 41751 - 41754
(2016/05/24)
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- Visible-light-induced regioselective synthesis of polyheteroaromatic compounds
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A method for visible-light-induced synthesis of polyheteroaromatics from 2-heteroaryl-substituted anilines and heteroarylalkynes was developed. The process, which uses fac-Ir(ppy)3 as the photocatalyst and tBuONO as the diazotization reagent, is highly regioselective.
- Chatterjee, Tanmay,Choi, Myung Gil,Kim, Jun,Chang, Suk-Kyu,Cho, Eun Jin
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supporting information
p. 4203 - 4206
(2016/03/19)
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- Potassium Hydroxide/Dimethyl Sulfoxide Superbase-Promoted Transition Metal-Free Synthesis of 2-Substituted Benzothiophenes under Visible Light
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A potassium hydroxide/dimethyl sulfoxide (KOH/DMSO) superbase-promoted method for the synthesis of 2-substituted benzothiophenes has been developed via photoinduced intermolecular annulation of 2-halothioanisoles with terminal alkynes at ambient temperature. The present protocol uses commercially available 2-halothioanisoles as substrates and visible light as energy force, which offers a wide range of benzothiophenes regioselectively in moderate to good yields. Such a facile and effective transformation will provide an environment-friendly approach to the synthesis of benzothiophene derivatives.
- Gao, Li,Chang, Bin,Qiu, Wenzhao,Wang, Lele,Fu, Xianzhi,Yuan, Rusheng
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p. 1202 - 1207
(2016/04/26)
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- Palladium(II) Catalyzed cyclization-carbonylation-cyclization coupling reaction of (ortho-Alkynyl Phenyl) (Methoxymethyl) Sulfides using molecular oxygen as the terminal oxidant
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An efficient PdII /Pd0 -p-benzoquinone/hydroquinone-CuCl2 /CuCl catalyst system was developed that uses environmentally friendly molecular oxygen as the terminal oxidant to catalyze the cyclization-carbonylation-cyclization coupling reaction (CCC-coupling
- Shen, Rong,Kusakabe, Taichi,Yatsu, Tomofumi,Kanno, Yuichiro,Takahashi, Keisuke,Nemoto, Kiyomitsu,Kato, Keisuke
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- A benzothiophene compound preparation method and its purification method
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The invention discloses a preparation method for benzothiophene compounds. The preparation method comprises the following steps: 1-bromine(chlorine)-2-styrene benzene or derivatives thereof are used as a substrate; a vulcanizer is added into the substrate
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Paragraph 0038
(2017/03/28)
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- HETERO-CYCLIC COMPOUND AND ORGANIC LIGHT EMITTING DEVICE USING THE SAME
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In the present invention, provided are: a heterocyclic compound which can significantly extend lifespan and improve efficiency, electrochemical stability, and thermal stability of the organic light-emitting device; and an organic light-emitting device containing the heterocyclic compound in an organic compound layer. The heterocyclic compound is represented by chemical formula 1.COPYRIGHT KIPO 2016
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Paragraph 0192-0193; 0198-199
(2016/10/08)
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- Preparation of Benzothiophenes and Benzoselenophenes from Arylamines and Alkynes via Radical Cascade Reactions
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An intermolecular radical cascade reaction between readily prepared o-methylthio-arylamines or o-methylselanyl-arylamines and alkynes for the preparation of valuable benzothiophenes or benzoselenophenes is reported. These transformations occur efficiently with complete regioselectivity and the products are obtained in moderate to good yields. The current protocol is successfully applied to the synthesis of the key intermediates of the drug raloxifene and an AT1receptor antagonist.
- Zang, Hao,Sun, Jian-Guo,Dong, Xin,Li, Ping,Zhang, Bo
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supporting information
p. 1746 - 1752
(2016/06/09)
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