- Ipso- borylation of aryl ethers via Ni-Catalyzed C-OMe Cleavage
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A Ni-catalyzed ipso-borylation of aryl ethers via C(sp2)-OMe and C(sp3)-OMe cleavage is described. The transformation is characterized by its wide substrate scope under mild conditions and an exquisite divergence in site selectivity that can be easily switched by selecting the appropriate boron reagent.
- Zarate, Cayetana,Manzano, Rubén,Martin, Ruben
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supporting information
p. 6754 - 6757
(2015/06/16)
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- C-H activation by amide chelation control: Ruthenium-catalyzed direct synthesis of 2-Aryl-3-furanamides
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A new, catalytic methodology for the synthesis of heterobiaryls by the ruthenium-catalyzed C-H activation/cross-coupling of heterocyclic amides with aryl boroneopentylates is surveyed. From this survey, the highly regioselective reaction of furan-3-carboxamide to give 2-aryl-3-furanamides is optimized and generalized in scope with respect to the aryl boroneopentylate coupling partners. Established thereby is a one-step synthetic method which may supercede the broadly applied two-step directed ortho metalation (DoM)-cross coupling reaction involving cryogenic and strong base conditions and which has potential for further ortho and remote metalation chemistry.
- Zhao, Yigang,Snieckus, Victor
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supporting information
p. 1527 - 1532
(2014/06/09)
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- Beyond directed ortho metalation: Ru-catalyzed CAr-O activation/cross-coupling reaction by amide chelation
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Disclosed is a new, catalytic, and general methodology for the chemical synthesis of biaryl, heterobiaryl, and polyaryl molecules by the cross-coupling of o-methoxybenzamides with aryl boroneopentylates. The reaction is based on the activation of the unreactive C-OMe bond by the proximate amide directing group using catalytic RuH2(CO)(PPh3)3 conditions. A one-step, base-free coupling process is thereby established that has the potential to supersede the useful two-step directed ortho metalation/cross- coupling reaction involving cryogenic temperature and strong base conditions. High regioselectivity, orthogonality with the Suzuki-Miyaura reaction, operational simplicity, minimum waste, and convenient scale-up make these reactions suitable for industrial applications.
- Zhao, Yigang,Snieckus, Victor
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supporting information
p. 11224 - 11227
(2014/09/29)
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- Zero-valent metals accelerate the neopentylglycolborylation of aryl halides catalyzed by NiCl2-based mixed-ligand systems
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The highly active mixed-ligand catalytic system NiCl2(dppp)/dppf combined with the reducing effect of zerovalent Zn and of other metals was used to demonstrate a method for the dramatic acceleration of the rate and for the enhancement of the yi
- Leowanawat, Pawaret,Resmerita, Ana-Maria,Moldoveanu, Costel,Liu, Chi,Zhang, Na,Wilson, Daniela A.,Hoang, Lisa M.,Rosen, Brad M.,Percec, Virgil
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supporting information; experimental part
p. 7822 - 7828
(2011/02/22)
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- Neopentylglycolborylation of ortho -substituted aryl halides catalyzed by NiCl2-Based mixed-ligand systems
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NiCl2-based mixed-ligand systems were shown to be very effective catalysts for the neopentylglycolborylation of aryl iodides, bromides, and chlorides bearing electron-rich and electron-deficient ortho-substituents. Although NiCl2-based single-ligand catalytic systems were able to mediate neopentylglycolborylation of selected substrates, they were not as effective for all substrates, highlighting the value of the mixed-ligand concept. Optimization of the Ni(II)-catalyzed neopentylglycolborylation of 2-iodoanisole and methyl 2-iodobenzoate demonstrated that, while the role of ligand and coligand in the conversion of Ni(II) precatalyst to Ni(0) active catalyst cannot be ignored, a mixed-ligand complex is likely present throughout the catalytic cycle. In addition, protodeborylation and hydrodehalogenation were demonstrated to be the predominant side reactions of Ni(II)-catalyzed borylation of ortho-substituted aryl halides containing the electron-deficient carboxylate substituents. Ni(II) complexes in the presence of H2O and Ni(0) are responsible for the catalysis of these side reactions.
- Moldoveanu, Costel,Wilson, Daniela A.,Wilson, Christopher J.,Leowanawat, Pawaret,Resmerita, Ana-Maria,Liu, Chi,Rosen, Brad M.,Percec, Virgil
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supporting information; experimental part
p. 5438 - 5452
(2010/11/05)
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