- Oxalohydrazide Ligands for Copper-Catalyzed C?O Coupling Reactions with High Turnover Numbers
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Here, we report a class of ligands based on oxalohydrazide cores and N-amino pyrrole and N-amino indole units that generates long-lived copper catalysts for couplings that form the C?O bonds in biaryl ethers. These Cu-catalyzed coupling of phenols with aryl bromides occurred with turnovers up to 8000, a value which is nearly two orders of magnitude higher than those of prior couplings to form biaryl ethers and nearly an order of magnitude higher than those of any prior copper-catalyzed coupling of aryl bromides and chlorides. This ligand also led to copper systems that catalyze the coupling of aryl chlorides with phenols and the coupling of aryl bromides and iodides with primary benzylic and aliphatic alcohols. A wide variety of functional groups including nitriles, halides, ethers, ketones, amines, esters, amides, vinylarenes, alcohols and boronic acid esters were tolerated, and reactions occurred with aryl bromides in pharmaceutically related structures.
- Ray, Ritwika,Hartwig, John F.
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supporting information
p. 8203 - 8211
(2021/03/08)
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- Superacid-promoted synthesis of quinoline derivatives
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A series of vinylogous imines have been prepared from anilines and cinnamaldehydes. These substrates react in superacidic media to provide quinolines and related compounds. A mechanism for the conversion is proposed which involves the cyclization of dicationic superelectrophilic intermediates. Aromatization of the quinoline ring is thought to occur by superacid-promoted elimination of benzene.
- Klumpp, Douglas A.,Stentzel, Michael R.,Vuong, Hein
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supporting information
(2020/01/24)
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- Copper-Catalyzed Diaryl Ether Formation from (Hetero)aryl Halides at Low Catalytic Loadings
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Diaryl formation is achieved by coupling phenols and (hetero)aryl halides under the catalysis of CuI/N,N′-bis(2-phenylphenyl) oxalamide (BPPO) or CuI/N-(2-phenylphenyl)-N′-benzyl oxalamide (PPBO) at 90 °C using DMF or MeCN as the solvent. Only 0.2-2 mol % CuI and ligand are required for complete conversion, which represents the lowest catalytic loadings for a general Cu/ligand-catalyzed diaryl ether formation.
- Zhai, Yuntong,Chen, Xiaofei,Zhou, Wei,Fan, Mengyang,Lai, Yisheng,Ma, Dawei
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p. 4964 - 4969
(2017/05/12)
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- CuI/oxalamide catalyzed couplings of (hetero)aryl chlorides and phenols for diaryl ether formation
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Couplings between (hetero)aryl chlorides and phenols can be effectively promoted by CuI in combination with an N-aryl-N′-alkyl-substituted oxalamide ligand to proceed smoothly at 120 °C. For this process, N-aryl-N′-alkyl-substituted oxalamides are more effective ligands than bis(N-aryl)-substituted oxalamides. A wide range of electron-rich and electron-poor aryl and heteroaryl chlorides gave the corresponding coupling products in good yields. Satisfactory conversions were achieved with electron-rich phenols as well as a limited range of electron-poor phenols. Catalyst and ligand loadings as low as 1.5 mol % are sufficient for the scaled-up variants of some of these reactions. Aryl and alkyl: N-Aryl-N′-alkyl-substituted oxalamide ligands promote the CuI catalyzed coupling of (hetero)aryl chlorides and phenols at 120 °C more effectively than bis(N-aryl)-substituted oxalamides. A wide range of electron-rich and electron-poor aryl and heteroaryl chlorides were converted into the corresponding coupling products in good yields.
- Fan, Mengyang,Zhou, Wei,Jiang, Yongwen,Ma, Dawei
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supporting information
p. 6211 - 6215
(2016/05/24)
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- (2-Pyridyl)acetone-promoted Cu-catalyzed O-arylation of phenols with aryl iodides, bromides, and chlorides
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(Chemical Equation Presented) Employing (2-pyridyl)acetone as a new supporting ligand, the copper-catalyzed coupling reactions of aryl chlorides, aryl bromides, and aryl iodides with various phenols successfully proceeded in good yields under mild conditions. This reaction displays great functional groups compatibility and excellent reactive selectivity.
- Zhang, Qi,Wang, Deping,Wang, Xianyang,Ding, Ke
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supporting information; experimental part
p. 7187 - 7190
(2009/12/09)
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