- Synthesis of highly substituted fluorenones via metal-free TBHP-promoted oxidative cyclization of 2-(aminomethyl)biphenyls. Application to the total synthesis of nobilone
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Highly substituted fluorenones are readily prepared in mostly fair to good yields via metal- and additive-free TBHP-promoted cross-dehydrogenative coupling (CDC) of readily accessible N-methyl-2-(aminomethyl)biphenyls and 2-(aminomethyl)biphenyls. This methodology is compatible with numerous functional groups (methoxy, cyano, nitro, chloro, and SEM and TBS-protective groups for phenols) and was further utilized in the first total synthesis of the natural product nobilone.
- Bracher, Franz,Jourjine, Ilya A. P.,Krau?, Jürgen,Zeisel, Lukas
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supporting information
p. 2668 - 2679
(2021/11/30)
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- Pd-Catalysed Suzuki-Miyaura cross-coupling of aryl chlorides at low catalyst loadings in water for the synthesis of industrially important fungicides
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The Suzuki-Miyaura coupling reaction of electron-poor aryl chlorides in the synthesis of crop protection-relevant active ingredients in water is disclosed. Optimisation of the reaction conditions allowed running the reaction with 50 ppm of Pd-catalyst loading without an additional organic solvent in the cross-coupling reaction step in short reaction times. The system was optimised for the initial cross-coupling step of the large scale produced fungicides Boscalid, Fluxapyroxad and Bixafen up to 97% yield. It is also shown that the Suzuki-Miyaura reaction can be easily scaled up to 50 g using a simple product separation and purification using environmentally benign solvents in the work-up. To show the usability of this method, it was additionally applied in the three-step synthesis of the desired active ingredients.
- Goetz, Roland,Hashmi, A. Stephen K.,Orecchia, Patrizio,Petkova, Desislava Slavcheva,Rominger, Frank,Schaub, Thomas
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supporting information
p. 8169 - 8180
(2021/11/01)
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- High-performance sky-blue phosphorescent organic light-emitting diodes employing wide-bandgap bipolar host materials with thermally activated delayed fluorescence characteristics
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Up to date, several kinds of thermally activated delayed fluorescence (TADF) host molecules have been rapidly developed to fulfill the increasing demand of high-efficiency phosphorescent organic light-emitting diodes (PHOLEDs). Herein, three wide-bandgap TADF materials BPCN-Cz2Ph, BPCN-2Cz, and BPCN-3Cz are newly designed and synthesized as host materials for sky-blue PHOLEDs. By modulation of carbazole-units in the molecular skeleton, we find that the optimized molecules can realize both high triplet energies and balanced carrier transport properties with obvious TADF properties. The sky-blue PHOLEDs with ultralow phosphor doping ratio employing BPCN-Cz2Ph, BPCN-2Cz, and BPCN-3Cz as host materials demonstrate really high performance with alleviated roll-offs and achieve impressive current efficiencies (CEs) of 46.5 cd A?1, 50.0 cd A?1, and 34.5 cd A?1, power efficiencies (PEs) of 40.6 lm W?1, 46.8 lm W?1, and 34.8 lm W?1, and external quantum efficiencies (EQEs) of 22.2%, 24%, and 15.8%, respectively. More encouragingly, even at an applied luminance of 1000 cd m?2, the EQEs could maintain high levels of 21.0%, 21.5% and 12.8%, respectively, which represents the potential utility value of the new family of these molecules in blue PHOLEDs. Our molecular design strategy provides a practical way to construct promising wide-bandgap TADF host materials with an excellent combination of TADF property, high triplet energy, and balanced carrier-transporting ability for high-performance devices.
- Zhang, Yuan-Lan,Ran, Quan,Wang, Qiang,Tian, Qi-Sheng,Kong, Fan-Cheng,Fan, Jian,Liao, Liang-Sheng
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- 6-Arylphenanthridines from Aryl o-Biaryl Ketones with 1,1,1,3,3,3-Hexamethyldisilazane and Molecular Iodine
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Warming treatment of aryl o-biaryl ketones with 1,1,1,3,3,3-hexamethyldisilazane in the presence of Sc(OTf)3 in toluene, followed by the reaction with molecular iodine and K2CO3 in a mixture of THF and methanol at 60 °C gave the corresponding 6-arylphenanthridines in good to moderate yields. The present reaction is a one-pot method for the preparation of 6-arylphenanthridines from aryl o-biaryl ketones through the cyclization of imino-nitrogen-centered radicals that were generated from N-iodo aryl o-biaryl ketimines formed from the reaction of aryl biaryl ketimines with molecular iodine.
- Kobayashi, Eiji,Kishi, Atsushi,Togo, Hideo
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p. 7335 - 7347
(2019/11/22)
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- Process for synthesizing boscalid
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The invention discloses a process for synthesizing boscalid. The process comprises the following steps: (1) coupling o-chlorobenzonitrile with benzene to obtain 2-cyanobiphenyl, then carrying out chlorination, reduction and salt formation purification to obtain 4'-chloro-2-aminobiphenyl hydrochloride; (2) carrying out condensation reaction on the prepared 4'-chloro-2-aminobiphenyl hydrochloride and 2-chloronicotinoyl chloride to obtain the boscalid. The process for synthesizing the boscalid has the advantages of simple synthesis process, no need of complex aftertreatment, cheap and easily available basic chemical raw materials, and suitability for industrial production.
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Paragraph 0061-0064
(2019/05/02)
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- Carbazole derivatives and application of carbazole derivatives in electroluminescent device
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The invention discloses carbazole derivatives represented by formulas (1)-(3), and also discloses application of the carbazole derivatives as a host material in an OLED organic light-emitting layer orapplication of the carbazole derivatives in preparation of an electroluminescent device. The carbazole derivatives have a high triplet state, exhibits bipolar transport properties at the same time, and has high carrier mobility, matching of electron holes is more balanced, and exciton formation is facilitated; and when the carbazole derivatives are applied to the organic electroluminescent blue-light device, excellent performance, low voltage and high efficiency are achieved.
- -
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Paragraph 0053-0055
(2019/11/28)
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- Controllable Rh(III)-Catalyzed C-H Arylation and Dealcoholization: Access to Biphenyl-2-carbonitriles and Biphenyl-2-carbimidates
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A controllable Rh(III)-catalyzed C-H arylation and dealcoholization of benzimidates with arylboronic esters was developed, delivering various biphenyl-2-carbonitriles and biphenyl-2-carbimidates by simply tuning the reaction conditions. This approach features high efficiency, good functional group tolerance, and easy operation. It also provides an alternative pathway to thoroughly exploit the directing group in transition-metal-catalyzed C-H activations.
- Jiang, Bo,Wu, Songxiao,Zeng, Jing,Yang, Xiaobo
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p. 6573 - 6577
(2018/10/09)
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- An Active Palladium Colloidal Catalyst for the Selective Oxidative Heterocoupling of (Hetero)Aryl Boronic Acids
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A highly selective oxidative heterocoupling protocol for (hetero)aryl boronic acids with an active palladium colloidal catalyst was developed. The judicious choice of electronically different aryl boronic acids made possible such couplings under mild conditions, with air as oxidant, while embracing a wide substrate scope. This successful approach further allowed the development of a unique one-pot sequential oxidative heterocoupling/Suzuki–Miyaura cross-coupling tandem process for accessing substituted terphenyls.
- Sable, Vaibhav,Maindan, Karan,Bhilare, Shatrughn,Chrysochos, Nicolas,Schulzke, Carola,Kapdi, Anant R.
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supporting information
p. 2489 - 2498
(2018/09/10)
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- Integrating Organic Lewis Acid and Redox Catalysis: The Phenalenyl Cation in Dual Role
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In recent years, merging different types of catalysis in a single pot has drawn considerable attention and these catalytic processes have mainly relied upon metals. However, development of a completely metal free approach integrating organic redox and organic Lewis acidic property into a single system has been missing in the current literature. This study establishes that a redox active phenalenyl cation can activate one of the substrates by single electron transfer process while the same can activate the other substrate by a donor-acceptor type interaction using its Lewis acidity. This approach has successfully achieved light and metal-free catalytic C-H functionalization of unactivated arenes at ambient temperature (39 entries, including core moiety of a top-selling molecule boscalid), an economically attractive alternative to the rare metal-based multicatalysts process. A tandem approach involving trapping of reaction intermediates, spectroscopy along with density functional theory calculations unravels the dual role of phenalenyl cation.
- Ahmed, Jasimuddin,Chakraborty, Soumi,Jose, Anex,Sreejyothi,Mandal, Swadhin K.
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supporting information
p. 8330 - 8339
(2018/06/19)
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- Synthesis, characterization and evaluation of bulky bis(pyrazolyl)palladium complexes in Suzuki-Miyaura cross-coupling reactions
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Pyrazole-containing compounds have been used in recent times as ligands to stabilize metal complexes used as pre-catalysts in cross-coupling reactions. With various substituents at various positions in the pyrazole ring, the overall electrophilic and steric properties of the metal complexes can be fine-tuned. Herein, we report the synthesis of bulky pyrazole-based ligands by condensation of methyl 4-(bromomethyl)benzoate or benzyl bromide with various substituted pyrazole compounds. These ligands were utilised in the synthesis of bis(pyrazolyl)palladium(ii) complexes. The complexes' catalytic activity in Suzuki-Miyaura cross-coupling reactions was evaluated. Phenyl bearing pre-catalyst 7, at a catalyst loading of 0.33 mol%, successfully converted 98% of bromobenzene and phenylboronic acid to biphenyl in 4 h at 140 °C, while the tertiary butyl bearing pre-catalyst 8 converted up to 81% of the same substrates to biphenyl. An increase in conversion was seen for all pre-catalysts when an electron-withdrawing substituent was present on the aryl halide substrate, and the opposite was observed when the electron-withdrawing group was present on the phenyl boronic acid.
- Ocansey, Edward,Darkwa, James,Makhubela, Banothile C. E.
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p. 13826 - 13834
(2018/04/26)
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- Method for preparing 4'-chloro-2-aminobiphenyl
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The invention provides a method for preparing 4'-chloro-2-aminobiphenyl, which comprises: carrying out coupling by using p-chlorophenyl magnesium halide (III) and chlorobenzonitrile (II) as raw materials and using manganese salt as a catalyst to obtain 4'-chloro-2-cyanobiphenyl (IV); carrying out mixed hydrolysis on the 4'-chloro-2-cyanobiphenyl (IV) and alkali as well as hydrogen peroxide to obtain 4'-chloro-2-amido biphenyl (V); carrying out Hofmann degradation on the obtained 4'-chloro-2-amido biphenyl (V) to obtain the 4'-chloro-2-aminobiphenyl (I). The method disclosed by the invention has the characteristics of operation safety and good economic feasibility, and is suitable for industrial development.
- -
-
Paragraph 0026; 0028; 0029
(2018/07/30)
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- Manganese-Catalyzed Cross-Coupling of Aryl Halides and Grignard Reagents by a Radical Mechanism
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The substrate scope and the mechanism have been investigated for the MnCl2-catalyzed cross-coupling reaction between aryl halides and Grignard reagents. The transformation proceeds rapidly and in good yield when the aryl halide component is an aryl chloride containing a cyano or an ester group in the para position or a cyano group in the ortho position. A range of other substituents gave no conversion of the aryl halide or led to the formation of side products. A broader scope was observed for the Grignard reagents, where a variety of alkyl- and arylmagnesium chlorides participated in the coupling. Two radical-clock experiments were carried out, and in both cases an intermediate aryl radical was successfully trapped. The cross-coupling reaction is therefore believed to proceed by an SRN1 mechanism, with a triorganomanganate complex serving as the most likely nucleophile and single-electron donor. Other mechanistic scenarios were excluded based on the substrate scope of the aryl halide.
- Antonacci, Giuseppe,Ahlburg, Andreas,Fristrup, Peter,Norrby, Per-Ola,Madsen, Robert
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p. 4758 - 4764
(2017/09/07)
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- Strongly Directing Substituents in the Radical Arylation of Substituted Benzenes
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Although general interest in radical arylation reactions has grown rapidly in recent years, poor regioselectivities and the need to use a large excess of the radical-accepting arene have hindered their application to substituted benzenes. We now describe experimental and computational investigations into the substituent effects that lead to regioselective addition based on the recent discovery of anilines as outstanding substrates for radical arylations.
- Hofmann, Josefa,Clark, Timothy,Heinrich, Markus R.
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p. 9785 - 9791
(2016/10/31)
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- Mass production method for 4-chloro-2'-cyanobiphenyl
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The invention discloses a mass production method for 4-chloro-2'-cyanobiphenyl. The mass production method comprises the following steps: para chlorobromobenzene and magnesium chips in a mole ratio being (1:1)-(1:5) are added to anhydrous tetrahydrofuran for a reaction under protection of nitrogen, and a Grignard reagent is prepared; 2-chlorobenzonitrile, a manganese compound catalyst and anhydrous tetrahydrofuran are mixed, then the Grignard reagent is added slowly to the mixture for a reaction, tetrahydrofuran is recovered after the reaction through filtration and desolvation, toluene is added, the pH value is regulated with an acid to be 1-5, an organic phase is separated out, the solvent is removed, and 4-chloro-2'-cyanobiphenyl is obtained. The raw materials are cheap and easily available, the total yield is higher, aftertreatment is simpler, and less pollution is caused.
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Paragraph 0026; 0027; 0028; 0029; 0030; 0031; 0032-0035
(2017/04/22)
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- Synthesis of secondary amides from N-Substituted amidines by tandem oxidative rearrangement and isocyanate elimination
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In this work an efficient tandem process transforming N-substituted amidines into secondary amides has been described. The process involves N-acylurea formation by reaction of the substrate with bis(acyloxy)(phenyl)-λ3-iodane followed by isocyanate elimination. The periodinane reagents are obtained from the commercially available phenyl-iodine(III) diacetate [PhI(OAc)2, (PIDA)] by ligand exchange with carboxylic acids. The N-substituted amidine substrates are easily synthesized from readily available nitriles. The method is applicable for secondary amide synthesis, based on both aliphatic and (hetero)aromatic amines, including challenging amides consisting of sterically hindered acids and amines. Moreover, the protocol allows one to combine steric bulk with electron deficiency in the target amides (aniline based). Such compounds are difficult to synthesize efficiently based on classical condensation reactions involving carboxylic acids and amines. Overall, the synthetic protocol transforms a nitrile into a secondary amide in both aliphatic and (hetero)aromatic systems.
- Debnath, Pradip,Baeten, Mattijs,Lefvre, Nicolas,Van Daele, Stijn,Maes, Bert U. W.
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supporting information
p. 197 - 209
(2015/03/03)
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- Novel N-biphenyl-2-ylmethyl 2-methoxyphenylpiperazinylalkanamides as 5-HT7R antagonists for the treatment of depression
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5-HT7 receptor (5-HT7R) is a promising target for the treatment of depression and neuropathic pain. 5-HT7R antagonists exhibited antidepressant effects, while the agonists produced strong anti-hyperalgesic effects. In our efforts to discover selective 5-HT 7R antagonists or agonists, N-biphenylylmethyl 2- methoxyphenylpiperazinylalkanamides 1 were designed, synthesized, and biologically evaluated against 5-HT7R. Among the synthesized compounds, N-2′-chlorobiphenylylmethyl 2- methoxyphenylpiperazinylpentanamide 1-8 showed the best binding affinity with a Ki value of 8.69 nM and it was verified as a novel antagonist according to functional assays. The compound 1-8 was very selective over 5-HT1DR, 5-HT2AR, 5-HT3R, 5-HT5AR and 5-HT6R and moderately selective over 5-HT1AR, 5-HT1BR and 5-HT2CR. The novel 5-HT7R antagonist 1-8 exhibited an antidepressant effect at a dose of 25 mg/kg in the forced swimming test in mice and showed a U-shaped dose-response curve which typically appears in 5-HT7R antagonists such as SB-269970 and lurasidone.
- Kim, Youngjae,Tae, Jinsung,Lee, Kangho,Rhim, Hyewhon,Choo, Il Han,Cho, Heeyeong,Park, Woo-Kyu,Keum, Gyochang,Choo, Hyunah
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p. 4587 - 4596
(2014/10/15)
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- Palladium-catalyzed desulfitative cross-coupling of sodium arylsulfinates with aryl bromides and chlorides: An alternative convenient synthesis of biaryls
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An alternative method for synthesis of biaryls has been developed through the Pd catalyzed desulfitative coupling reaction of sodium arylsulfinates with aryl bromides and chlorides. The procedure tolerates a variety of functional groups, such as cyano, formyl, acetyl, chloro, methoxy, trifluoromethyl and heteroaromatic unit. The desired products were obtained in moderate to excellent yields under relatively mild reaction conditions without additives, base or co-catalyst. An alternative method for synthesis of biaryls has been developed through the Pd catalyzed desulfitative coupling reaction of sodium arylsulfinates with aryl bromides and chlorides. The procedure tolerates a variety of functional groups, such as cyano, formyl, acetyl, chloro, methoxy, trifluoromethyl and heteroaromatic unit. The desired products were obtained in moderate to excellent yields under relatively mild reaction conditions without additives, base or co-catalyst. Copyright
- Zhou, Chao,Li, Yaming,Lu, Yang,Zhang, Rong,Jin, Kun,Fu, Xinmei,Duan, Chunying
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p. 1269 - 1273
(2013/11/06)
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- Metal-free directed ortho C-H iodination: Synthesis of 2'-iodobiaryl-2- carbonitriles
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Metal-free directed ortho C-H iodination of biaryl-2-carbonitriles was developed. A series of 2'-iodobiaryl-2-carbonitriles were synthesized from substituted biphenylcarbonitriles and naphthylbenzonitriles in reasonably good yields by using bis(pyridine)iodonium(I) tetrafluoroborate (IPy 2BF4, Barluenga's reagent) and HBF4· OEt2. The biaryl-2-carbonitriles are useful precursors for the synthesis of benzocyclic ketones. Metal-free directed ortho C-H iodination of biaryl-2-carbonitriles is efficiently performed in good yields by using bis(pyridine)iodonium(I) tetrafluoroborate (IPy2BF4, Barluenga's reagent) and HBF4·OEt2. Copyright
- Sarkar, Satinath,Jana, Manoranjan,Narender, Tadigoppula
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supporting information
p. 6491 - 6495
(2013/11/06)
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- Novel syntheses of fluorenones via nitrile-directed palladium-catalyzed C-H and dual C-H bond activation
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Novel procedures for the [Pd]/[Ag]/TFA system catalyzed cascade reactions of nitrile directed remote C-H and dual C-H bond activation with insertion of nitrile were developed, which afforded variously polysubstituted fluorenones in moderate to good yields with tolerance of a wide variety of substrates.
- Wan, Jung-Chih,Huang, Jun-Min,Jhan, Yu-Huei,Hsieh, Jen-Chieh
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supporting information
p. 2742 - 2745
(2013/07/19)
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- Synthesis, characterization and catalytic activity of palladium complexes with α-imino-amidos ligands
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In the present work, a series of steric substituted α-imino-amido palladium complexes, {[Ar-NC(CH3)-C(CH3)(R)-NH-Ar] PdCl2} (C1, R = Me, Ar = 2,6-dimethylphenyl; C2, R = Me, Ar = 2,6-diisopropylphenyl; C3, R = CH2Ph, Ar = 2,6-dimethylphenyl; C4, R = CH2Ph, Ar = 2,6-diisopropylphenyl), were synthesized and characterized. The structures of palladium complexes C3 and C4 were elucidated by X-ray diffraction. These bidentate nitrogen ligands were applied in palladium-catalyzed Suzuki-Miyaura cross-coupling reactions. The effect of ligand substitution as well as reaction conditions on catalytic activity was evaluated. Under the optimization process, the less bulky and electron-donating ligand were successfully used to catalyze the reaction of a variety of aryl bromides and chlorides with arylboronic acids, giving the desired biaryl products in high yields.
- Cao, Gao,Yang, Hai-Qing,Luo, Bao-Tian,Liu, Feng-Shou
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p. 158 - 165
(2013/10/01)
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- Palladium-catalyzed desulfitative arylation by C-O bond cleavage of aryl triflates with sodium arylsulfinates
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An efficient Pd-catalyzed desulfitative coupling reaction of sodium arylsulfinates as arylation reagents by C-O bond cleavage of aryl triflates was developed. With only 2 mol % of Pd(OAc)2 as catalyst and XPhos as ligand, the reaction proceeded well for a range of substrates.
- Zhou, Chao,Liu, Qingjiang,Li, Yaming,Zhang, Rong,Fu, Xinmei,Duan, Chunying
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p. 10468 - 10472
(2013/01/15)
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- A highly practical and reliable nickel catalyst for Suzuki-Miyaura coupling of aryl halides
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We disclose that [1,3-bis(diphenylphosphino)methane]nickel(II) chloride [NiCl2(dppp)] is a highly active, universally applicable, cheap, and stable catalyst for Suzuki-Miyaura cross-coupling reactions of aryl halides with a catalyst loading of lower than 1 mol%, and more notably, in the absence of extra supporting ligands. Under the optimized reaction conditions, a broad range of aryl bromides as well as the notoriously unreactive aryl chlorides, including activated, non-activated, deactivated, and heteroaromatic and sterically hindered substrates can be coupled smoothly with various boronic acids (47 examples, 48-98% yields). In addition, the transformation is tolerant of various functional groups such as ether, ester, ketone, aldehyde, cyano, and unprotected amino and hydroxy groups. Finally, the potential utilization of the methodology was further demonstrated by the gram-scale synthesis of several core structures of commercialized antihypertensive drugs and fungicides. Thus, the combination of high activity, broad applicability, cheapness, and high stability of NiCl2(dppp) presented in this work constitutes one of the few prominent catalysts which allow for practical and reliable construction of biaryls and heterobiaryls with structural diversity from readily available aryl halides and boronic acids. Copyright
- Zhao, Yu-Long,Li, You,Li, Shui-Ming,Zhou, Yi-Guo,Sun, Feng-Yi,Gao, Lian-Xun,Han, Fu-She
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supporting information; experimental part
p. 1543 - 1550
(2011/08/07)
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- Synthesis of biphenyl-2-carbonitrile derivatives via a palladium-catalyzed sp2 C-H bond activation using cyano as a directing group
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PdII-catalyzed aromatic C-H bond activation using cyano as a directing group was carried out in TFA medium. Biphenyl-2-carbonitrile derivatives were therefore synthesized from aryl nitriles and aryl halides in moderate to good yields.
- Li, Wu,Xu, Zhipeng,Sun, Peipei,Jiang, Xiaoqing,Fang, Min
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supporting information; experimental part
p. 1286 - 1289
(2011/04/26)
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- Copper-catalyzed synthesis of phenanthridine derivatives under an oxygen atmosphere starting from biaryl-2-carbonitriles and grignard reagents
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A copper-catalyzed synthesis of phenanthridine derivatives was developed starting from biaryl-2-carbonitriles and Grignard reagents. The present transformation is carried out by a sequence of nucleophilic addition of Grignard reagents to biaryl-2-carbonitriles to form N-H imines and their Cu-catalyzed C-N bond formation on the aromatic C-H bond, where molecular oxygen is a prerequisite to achieve the catalytic process.
- Zhang, Line,Ang, Gim Yean,Chiba, Shunsuke
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supporting information; experimental part
p. 3682 - 3685
(2010/10/20)
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- Novel Rh(I)-catalyzed reaction of arylzinc compounds with methyl halides
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The cross-coupling reactions of arylzinc compounds with methyl iodide or substituted methyl halides like benzyl bromides took place smoothly by the catalysis of Rh(I)-dppf complex.
- Hossain, Kabir M.,Takagi, Kentaro
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p. 1241 - 1242
(2007/10/03)
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- Ultrasound-Promoted Synthesis of Arylzinc Compounds Using Zinc Powder and Their Application to Palladium(0)-Catalyzed Synthesis of Multifunctional Biaryls
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Arylzinc compounds containing electron-withdrawing groups such as CO2CH3, CON(CH3)2, CN, Br, Cl, or CF3 at ortho position were prepared readily by the ultrasound-promoted reaction of aryl iodides with zinc powder, which were applied to palladium(0)-catalyzed cross-coupling with aryl halides to afford unsymmetrical and multifunctional biaryls in good yields.
- Takagi, Kentaro
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p. 469 - 472
(2007/10/02)
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- Phase-Transfer-Catalyzed Gomberg-Bachmann Synthesis of Unsymmetrical Biarenes: A Survey of Catalysts and Substrates
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Two problems have hindered the Gomberg-Bachmann (GB) and Pschorr reactions of arenediazonium cations: the instability of the arenediazonium salts and side reactions.Arenediazonium tetrafluoroborate and hexafluorophosphate salts can be prepared in high yield and purity and can be stored safely.Unfortunately, these salts are insoluble in most nonpolar organic solvents.Crown ether complexation or other phase-transfer (pt) catalytic methodology can ameliorate this situation, and reactions conducted by the approaches outlined herein often afforded coupling or cyclization products in high yield and corresponding purity.The use of crown ethers, quarternary 'onium salts, lipophilic carboxylic acid salts, and even the polar cosolvent acetonitrile increase the utility of the ptGB reaction dramatically.Sixty examples of couplings are reported along with an assessment of selectivities.A number of examples are also presented of phase-transfer-type Pschorr cyclizations.In the latter case, the use of potassium superoxide, KO2, is introduced to suppress indazole formation.
- Beadle, James R.,Korzeniowsky, Stephen H.,Rosenberg, David E.,Garcia-Slanga, Blanche J.,Gokel, George W.
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p. 1594 - 1603
(2007/10/02)
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