- Bipyridine-Type Bidentate Auxiliary-Enabled Copper-Mediated ?C-H/C-H Biaryl Coupling of Phenols and 1,3-Azoles
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A copper-mediated dehydrogenative C-H/C-H biaryl coupling of phenols and 1,3-azoles has been developed. The key to its success is the introduction of a bipyridine-type bidentate auxiliary, 4,4′-di(tert-butyl)-2,2′-bipyridine, on the phenol oxygen, which is readily prepared and easily attachable, detachable, and recyclable. The reaction proceeds smoothly in the presence of copper salt alone to form the corresponding phenol-azole heterobiaryls, which are prevalent motifs in functional molecules such as excited-state intramolecular proton transfer materials.
- Hirano, Koji,Kajiwara, Rikuo,Miura, Masahiro,Xu, Shibo
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- Rhodium(III)-Catalyzed ortho-Heteroarylation of Phenols through Internal Oxidative C-H Activation: Rapid Screening of Single-Molecular White-Light-Emitting Materials
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Reported herein is the first example of a transition-metal-catalyzed internal oxidative C-H/C-H cross-coupling between two (hetero)arenes through a traceless oxidation directing strategy. Without the requirement of an external metal oxidant, a wide range of phenols, including phenol-containing natural products, can undergo the coupling with azoles to assemble a large library of highly functionalized 2-(2-hydroxyphenyl)azoles. The route provides an opportunity to rapidly screen white-light-emitting materials. As illustrative examples, two bis(triphenylamine)-bearing 2-(2-hydroxyphenyl)oxazoles, which are difficult to access otherwise, exhibit bright white-light emission, high quantum yield, and thermal stability. Also presented is the first example of the white-light emission, in a single excited-state intramolecular proton transfer system, of 2-(2-hydroxyphenyl)azoles, thus highlighting the charm of C-H activation in the discovery of new organic optoelectronic materials.
- Li, Bijin,Lan, Jingbo,Wu, Di,You, Jingsong
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p. 14008 - 14012
(2016/01/25)
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- Simple and efficient preparation of 2,5-disubstituted oxazoles via a metal-free-catalyzed cascade cyclization
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A practical and simple synthesis of 2,5-disubstituted oxazoles was developed via an iodine-catalyzed tandem oxidative cyclization. A wide range of common commercial aromatic aldehydes can be used as reaction substrates, which displayed excellent functional group compatibility in this reaction.
- Wan, Changfeng,Gao, Linfeng,Wang, Qiang,Zhang, Jintang,Wang, Zhiyong
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supporting information; experimental part
p. 3902 - 3905
(2010/11/04)
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- The Unambiguous Syntheses of the 2,5-Diphenyloxazole Metabolites
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The syntheses of the six possible monoxydroxy derivatives and the N-oxide of 2,5-diphenyloxazole are described.Attempts towards the synthesis of 2,5-diphenyloxazol-4(5H)-one are also reported.
- Jacobsen, Noel W.,Philippides, Athena
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p. 1335 - 1338
(2007/10/02)
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