- Photoinduced Heterogeneous C?H Arylation by a Reusable Hybrid Copper Catalyst
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Heterogeneous copper catalysis enabled photoinduced C?H arylations under exceedingly mild conditions at room temperature. The versatile hybrid copper catalyst provided step-economical access to arylated heteroarenes, terpenes and alkaloid natural products with various aryl halides. The hybrid copper catalyst could be reused without significant loss of catalytic efficacy. Detailed studies in terms of TEM, HRTEM and XPS analysis of the hybrid copper catalyst, among others, supported its outstanding stability and reusability.
- Choi, Isaac,Müller, Valentin,Lole, Gaurav,K?hler, Robert,Karius, Volker,Vi?l, Wolfgang,Jooss, Christian,Ackermann, Lutz
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supporting information
p. 3509 - 3514
(2020/03/03)
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- Palladium-catalyzed direct C2-arylation of azoles with aromatic triazenes
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A highly efficient palladium-catalyzed arylation of azoles at the C2-position using 1-aryltriazenes as aryl reagents was developed. Azoles including oxazoles, thiazoles, imidazoles, 1,3,4-oxadiazoles, and oxazolines could react with 1-aryltriazenes smoothly to generate the corresponding products in good to excellent yields, and various substitution patterns were tolerated toward the reaction.
- Liu, Can,Wang, Zhiming,Wang, Lei,Li, Pinhua,Zhang, Yicheng
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p. 9209 - 9216
(2019/11/05)
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- Mixed N-heterocycles/N-heterocyclic carbene palladium(II) allyl complexes as precatalysts for direct arylation of azoles with aryl bromides
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A series of mixed N-heterocycles/N-heterocyclic carbene palladium(II) allyl complexes with general formula [(NHC)Pd(η3-allyl)]2(μ2-N-heterocycles)(BF4)2 were prepared in one pot based on anion metathesis of (NHC)Pd(η3-allyl)Cl complexes and then ligand replacement with N-heterocycles [N-heterocycles = pyrazine (pyz), 4,4′-bipyridine (bpy) and trans-4,4′-bipyridylethylene (bpe)]. The solid-state structures shown dinuclear structures with two palladium(II) centers holding together by bridged N-heterocycles. Initially investigation of the obtained complexes as precatalysts for direct C[sbnd]H bond arylation of azoles with aryl bromides was carried out.
- Yang, Jin
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p. 2182 - 2187
(2019/02/24)
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- A new face of phenalenyl-based radicals in the transition metal-free C-H arylation of heteroarenes at room temperature: Trapping the radical initiator: Via C-C σ-bond formation
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The radical-mediated transition metal-free approach for the direct C-H bond functionalization of arenes is considered as a cost effective alternative to transition metal-based catalysis. An organic ligand-based radical plays a key role by generating an aryl radical which undergoes a subsequent functionalization process. The design principle of the present study takes advantage of a relatively stable odd alternant hydrocarbon-based phenalenyl (PLY) radical. In this study, the first transition metal-free catalyzed direct C-H arylation of a variety of heteroarenes such as azoles, furan, thiophene and pyridine at room temperature has been reported using a phenalenyl-based radical without employing any photoactivation step. This protocol has been successfully applied to the gram scale synthesis of core moieties of bioactive molecules. The phenalenyl-based radical initiator has been characterized crystallographically by trapping it via the formation of a C-C σ-bond between the phenalenyl radical and solvent-based radical species.
- Ahmed, Jasimuddin,Sreejyothi,Vijaykumar, Gonela,Jose, Anex,Raj, Manthan,Mandal, Swadhin K.
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p. 7798 - 7806
(2017/10/30)
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- Palladium-Catalyzed Zinc-Amide-Mediated C-H Arylation of Fluoroarenes and Heteroarenes with Aryl Sulfides
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C-H arylation of polyfluoroarenes and heteroarenes with aryl sulfides proceeds smoothly with the aid of a palladium-N-heterocyclic carbene catalyst. A bulky zinc amide, TMPZnCl an effective base to generate the corresponding arylzinc species in situ. This arylation protocol is practically much easier to perform than our previous method, which necessitates preparation of the arylzinc reagents in advance from the corresponding aryl halides. Aryl sulfides that are prepared through sulfur-specific reactions, such as SNAr sulfanylation and extended Pummerer reactions, undergo this direct arylation, offering interesting transformations that are otherwise difficult to achieve with conventional halogen-based organic synthesis.
- Otsuka, Shinya,Yorimitsu, Hideki,Osuka, Atsuhiro
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supporting information
p. 14703 - 14707
(2015/10/20)
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- Programmed synthesis of arylthiazoles through sequential C-H couplings
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A programmed synthesis of privileged arylthiazoles via sequential C-H couplings catalyzed by palladium or nickel catalysts has been accomplished. This versatile protocol can supply all possible arylthiazole substitution patterns (2-aryl, 4-aryl, 5-aryl, 2
- Tani, Satoshi,Uehara, Takahiro N.,Yamaguchi, Junichiro,Itami, Kenichiro
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p. 123 - 135
(2014/01/06)
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- DDQ-induced dehydrogenation of heterocycles for c-c double bond formation: Synthesis of 2-thiazoles and 2-oxazoles
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Strong as an Ox: 2-Thiazoles and 2-oxazoles are formed by oxidation of 2-thiazolines and 2-oxazolines without requiring substituents at the C4 and C5 positions. DDQ plays an important role as the oxidant in this transformation and metal is unnecessary. This general procedure shows good functional group tolerance and provides a wide variety of 2-thiazoles and 2-oxazoles in moderate to excellent yields.
- Li, Xiangnan,Li, Cheng,Yin, Bing,Li, Cong,Liu, Ping,Li, Jianli,Shi, Zhen
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p. 1408 - 1411
(2013/07/26)
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- Kumada-Tamao-Corriu coupling of heteroaromatic chlorides and aryl ethers catalyzed by (IPr)Ni(allyl)Cl
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The complex (IPr)Ni(allyl)Cl (IPr = 1,3-bis(2,6-diisopropylphenyl) imidazolidene) catalyzes the cross-coupling reactions of heteroaromatic chlorides with aryl Grignard reagents. Catalyst loadings as low as 0.1 mol % have been used to afford the products in excellent yields. This nickel-based catalytic system also promotes the activation of the CAr-O bond of anisoles in the Kumada-Tamao-Corriu reaction under fairly mild conditions.
- Iglesias, Maria Jose,Prieto, Auxiliadora,Nicasio, M. Carmen
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supporting information
p. 4318 - 4321
(2012/10/29)
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- Palladium-catalyzed desulfitative arylation of azoles with arylsulfonyl hydrazides
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Palladium-catalyzed desulfitative and denitrogenative arylation of azoles with arylsulfonyl hydrazides has been achieved. A broad scope of azoles and arylsulfonyl hydrazides has been used to produce arylated azoles in high yields.
- Yu, Xinzhang,Li, Xingwei,Wan, Boshun
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p. 7479 - 7482
(2012/10/29)
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- Palladium-catalyzed deamidative arylation of azoles with arylamides through a tandem decarbonylation-C-H functionalization
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A highly chemo-, regio-selective, and efficient palladium-catalyzed deamidative arylation of azoles with arylamides, as an aryl metal equivalent, has been developed. The reaction proceeds smoothly to generate the corresponding products in good yields via a tandem decarbonylation-C-H activation.
- Li, Chengliang,Li, Pinhua,Yang, Jin,Wang, Lei
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supporting information; experimental part
p. 4214 - 4216
(2012/05/04)
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- A highly efficient palladium-catalyzed desulfitative arylation of azoles with sodium arylsulfinates
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A highly efficient palladium-catalyzed direct desulfitative arylation of azoles at C2-position has been developed using sodium arylsulfinates as aryl sources. Azoles including benzoxazoles, benzothiazoles, oxazoles, thiazoles, and 1,3,4-oxadiazoles reacted with sodium arylsulfinates smoothly to generate the corresponding products in good to excellent yields, and various substitution patterns were tolerated toward the reaction.
- Wang, Min,Li, Dengke,Zhou, Wei,Wang, Lei
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experimental part
p. 1926 - 1930
(2012/03/26)
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- Nanocrystalline titania-supported palladium(0) nanoparticles for Suzuki-Miyaura cross-coupling of aryl and heteroaryl halides
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The Suzuki cross-coupling reaction of various aryl and heteroaryl halides with arylboronic and heteroarylboronic acids was studied using a titania-supported palladium(0) catalyst at room temperature under air. The conversion and selectivity results obtained for many substrates were excellent and similar to those provided by more active or even homogeneous catalysts. The methodology is similarly effective using 2-bromo-3,4,5-trimethoxybenzaldehyde as the coupling partner and gave products in good yield. Furthermore, it has been shown that it is useful for the synthesis of terphenyl and tetraphenyls. The catalyst is quantitatively recovered from the reaction by simple filtration and reused for a number of cycles without significant loss of activity. Inductively coupled plasma (ICP) mass-spectrometric analysis of the filtrate from the reaction mixture demonstrated that the palladium metal hardly leached into the solution within the limits of the detector (1 ppm), thus suggesting that the present Suzuki-Miyaura reaction proceeded by heterogeneous catalysis. Copyright
- Sreedhar,Yada, Divya,Reddy, P. Surendra
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experimental part
p. 2823 - 2836
(2011/12/01)
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- Palladium-catalyzed C-H functionalization of heteroarenes with aryl bromides and chlorides
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Palladium-catalyzed C-H arylation of electron-enriched heteroarenes with aryl bromides and aryl chlorides proceeds in the presence of LiO-t-Bu as a base. The reaction allows one-pot synthesis of differently substituted 2,5-diarylthiazole with the same catalyst system by switching the solvent and the amount of base.
- Tamba, Shunsuke,Okubo, Youhei,Tanaka, Shota,Monguchi, Daiki,Mori, Atsunori
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supporting information; experimental part
p. 6998 - 7001
(2010/11/24)
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- Nickel-catalyzed direct arylation of azoles with aryl bromides
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Nickel catalyst systems for the direct C2 arylation of oxazoles and thiazoles have been developed. The catalyst systems are cost-efficient and allow the use of various aryl bromides in the C-H arylation of azoles.
- Hachiya, Hitoshi,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information; experimental part
p. 1737 - 1740
(2009/09/06)
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- Direct arylation of thiazoles on water
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Wetter is better: The direct arylation of thiazoles on water is quicker, cleaner, and higher-yielding than arylation in organic solvents. The reaction works under mild conditions for an array of aryl iodides, producing 2,5-diaryl thiazoles in excellent yields. Importantly, novel bi-heteroaryl compounds are produced without the requirement for stoichiometric organometallic coupling agents. (Figure Presented).
- Turner, Gemma L.,Morris, James A.,Greaney, Michael F.
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p. 7996 - 8000
(2008/09/17)
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