- Ru(II)-Catalyzed Chemoselective C(sp3)-H Monoarylation of 8-Methyl Quinolines with Arylboronic Acids
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The transition-metal-promoted C-H activation has become an efficient as well as atom-economic methodology for the synthesis of a wide array of organic molecules, but the cost of the metal catalyst and selectivity remain the major challenges. Herein, the first [Cl2Ru(p-cymene)]2-catalyzed direct monoarylation of unactivated C(sp3)-H bonds of 8-methyl quinolines with arylboronic acids to synthesize diarylmethane compounds is presented. The transformation shows a broad substrate scope with high chemoselectivity for the synthesis of 8-benzyl quinolines. In the preliminary mechanistic studies, control experiments, deuterium labeling experiments, and kinetic studies have been performed.
- Parmar, Diksha,Kumar, Rohit,Kumar, Rakesh,Sharma, Upendra
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p. 11844 - 11855
(2020/10/23)
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- Cp*RhIII-Catalyzed Sterically Controlled C(sp3)?H Selective Mono- and Diarylation of 8-Methylquinolines with Organoborons
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Herein, the RhIII-catalyzed selective monoarylation and diarylation (symmetrical and unsymmetrical) of 8-methylquinolines with organoboron reagents are disclosed. The selective monoarylation of primary C(sp3)?H bonds is achieved by using 7-substituted 8-methylquinolines or by changing the quantity of the aryl boronic acids. The method is also applicable for the arylation of 2-ethylpyridines, and the heteroarylation with thiophene-2-ylboronic acids. Symmetrical and unsymmetrical diarylation of 8-methylquinolines have been carried out in one-pot and sequential manner, respectively. Late-stage monoarylation of oxime derivatives and gram-scale synthesis of monoarylated products has also been carried out. A mechanistic study revealed that the current reaction is first order with respect to both reactants and a five-membered rhodacycle intermediate may be involved in the catalytic cycle.
- Chandra, Devesh,Dhiman, Ankit Kumar,Gupta, Shiv Shankar,Kumar, Rakesh,Parmar, Diksha,Sharma, Upendra
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supporting information
(2020/03/23)
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- Pd-Catalyzed Alkylation of (Iso)quinolines and Arenes: 2-Acylpyridine Compounds as Alkylation Reagents
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The first Pd-catalyzed alkylation of (iso)quinolines and arenes is reported. The readily available and bench-stable 2-acylpyridine compounds were used as an alkylation reagent to form the structurally versatile alkylated (iso)quinolines and arenes. The method affords a convenient pathway for the introduction of alkyl groups into organic molecules.
- Wu, Qingsong,Han, Shuaijun,Ren, Xiaoxiao,Lu, Hongtao,Li, Jingya,Zou, Dapeng,Wu, Yangjie,Wu, Yusheng
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p. 6345 - 6348
(2018/10/20)
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- CpRhIII-Catalyzed Arylation of C(sp3) Bonds
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The first CpRhIII-catalyzed arylation of unactivated C(sp3) bonds is presented. The unactivated primary C(sp3) bond of 2-alkylpyridines can be activated by RhIII and further reacts with triarylboroxines to efficiently build new C(sp3)-aryl bonds. The methodology also provides a facile and efficient synthesis of unsymmetrical triarylmethanes by RhIII-catalyzed C(sp3) arylation of diarylmethanes. Unactivated! The unactivated primary C(sp3) bond of 2-alkylpyridines can be activated by RhIII and then react with triarylboroxines to efficiently build new C(sp3)-aryl bonds (see scheme, DG=directing group, FG=functional group). The methodology also provides a facile and efficient synthesis of unsymmetrical triarylmethanes by RhIII-catalyzed C(sp3) arylation.
- Wang, Xiaoming,Yu, Da-Gang,Glorius, Frank
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supporting information
p. 10280 - 10283
(2015/09/01)
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- Chelation-assisted palladium-catalyzed acyloxylation of benzyl sp3 C-H bonds using PhI(OAc)2 as oxidant
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A chelation-assisted palladium-catalyzed acyloxylation of the sp3 C-H bond of benzyl by carboxylic acid is described, which employs PhI(OAc)2 as a stoichiometric oxidant. The procedure tolerates a series of functional groups, such as
- Zhang, Shouhui,Luo, Fang,Wang, Wenhui,Jia, Xiaofei,Hu, Maolin,Cheng, Jiang
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supporting information; experimental part
p. 3317 - 3319
(2010/07/10)
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- Palladium-catalyzed decarboxylative arylation of C-H bonds by aryl acylperoxides
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A Pd(OAc)2-catalyzed protocol for decarboxylative arylation of aromatic C-H bond was developed using aryl acylperoxides as inexpensive aryl sources. Substrates containing pyridyl, oxime, and oxazoline groups undergo effectively ortho-selective C-H arylation with excellent functional group tolerance. This arylation should begin by directing-group-assisted cyclopalladation, followed by the reaction of the palladacycle with aryl radicals generated in situ by thermal decomposition of the peroxides.
- Yu, Wing-Yiu,Sit, Wing Nga,Zhou, Zhongyuan,Chan, Albert S.-C.
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supporting information; experimental part
p. 3174 - 3177
(2009/11/30)
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- Catalytic and highly regioselective cross-coupling of aromatic C-H substrates
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This communication describes a new Pd-catalyzed reaction for the highly chemo- and regioselective oxidative cross-coupling of aromatic C-H bonds. This transformation is proposed to proceed via two discrete C-H activation steps whose selectivities are pred
- Hull, Kami L.,Sanford, Melanie S.
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p. 11904 - 11905
(2008/03/30)
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- Palladium-catalyzed fluorination of carbon-hydrogen bonds
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This communication describes the development of a new Pd-catalyzed method for the fluorination of carbon-hydrogen bonds. A key step of these transformations involves palladium-mediated carbon-fluorine couplinga much sought after, but previously unpreceden
- Hull, Kami L.,Anani, Waseem Q.,Sanford, Melanie S.
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p. 7134 - 7135
(2007/10/03)
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- Oxidative C-H activation/C-C bond forming reactions: Synthetic scope and mechanistic insights
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This paper describes a new palladium-catalyzed method for C-H activation/carbon-carbon bond formation with hypervalent iodine arylating agents. This transformation has been applied to a variety of arene and benzylic substrates containing different directing groups (pyridines, quinolines, oxazolidinones, and amides) and proceeds with high levels of regiocontrol. Mechanistic experiments provide preliminary evidence in support of an unusual mechanism for this transformation involving a Pd(II)/Pd(IV) catalytic cycle. Copyright
- Kalyani, Dipannita,Deprez, Nicholas R.,Desai, Lopa V.,Sanford, Melanie S.
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p. 7330 - 7331
(2007/10/03)
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