1702-67-6Relevant articles and documents
The reaction pattern of the MoCl5-mediated oxidative aryl-aryl coupling
Waldvogel, Siegfried R.
, p. 622 - 624 (2002)
The oxidative coupling of electron rich aryls by molybdenum pentachloride is reported. The stoichiometry of the coupling reaction reveals that MoCl5 is a single electron acceptor. Interestingly, the 1,2-dialkoxy substitution pattern is pivotal for the arylaryl coupling.
Carbocatalytic Oxidative Dehydrogenative Couplings of (Hetero)Aryls by Oxidized Multi-Walled Carbon Nanotubes in Liquid Phase
Wirtanen, Tom,Aikonen, Santeri,Muuronen, Mikko,Melchionna, Michele,Kemell, Marianna,Davodi, Fatemeh,Kallio, Tanja,Hu, Tao,Helaja, Juho
, p. 12288 - 12293 (2019)
HNO3-oxidized carbon nanotubes catalyze oxidative dehydrogenative (ODH) carbon–carbon bond formation between electron-rich (hetero)aryls with O2 as a terminal oxidant. The recyclable carbocatalytic method provides a convenient and an operationally easy synthetic protocol for accessing various benzofused homodimers, biaryls, triphenylenes, and related benzofused heteroaryls that are highly useful frameworks for material chemistry applications. Carbonyls/quinones are the catalytically active site of the carbocatalyst as indicated by model compounds and titration experiments. Further investigations of the reaction mechanism with a combination of experimental and DFT methods support the competing nature of acid-catalyzed and radical cationic ODHs, and indicate that both mechanisms operate with the current material.
Anodic oxidation of hexamethoxybiphenyls into either stable cation radical salt or spiro(fluorene-9,1′-cyclohexadienones)
Douadi, Tahar,Cariou, Michel,Simonet, Jacques
, p. 4449 - 4456 (1996)
Three symmetrically substituted hexamethoxybiphenyls were subjected to electrooxidation at a platinum anode. 2,2′,4,4′,5,5′-hexamethoxybiphenyl led to the stable cation radical salt expected, whereas 3,3′,4,4′,5,5′-hexamethoxybiphenyl and 2,2′,3,3′,4,4′-h
Nitrosonium-Mediated Phenol-Arene Cross-Coupling Involving Direct C-H Activation
Eisenhofer, Anna,Wille, Uta,K?nig, Burkhard
, p. 407 - 412 (2017)
The nitrosonium ion (NO+) is a highly versatile nitration and nitrosation reagent, as well as a strong one-electron oxidant. Herein, we describe an environmentally benign and mild method for the in situ formation of NO+ from readily
Source of Selectivity in Oxidative Cross-Coupling of Aryls by Solvent Effect of 1,1,1,3,3,3-Hexafluoropropan-2-ol
Elsler, Bernd,Wiebe, Anton,Schollmeyer, Dieter,Dyballa, Katrin M.,Franke, Robert,Waldvogel, Siegfried R.
, p. 12321 - 12325 (2015)
Solvents such as 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) with a high capacity for donating hydrogen bonds generate solvates that enter into selective cross-coupling reactions of aryls upon oxidation. When electric current is employed for oxidation, reagent effects can be excluded and a decoupling of nucleophilicity from oxidation potential can be achieved. The addition of water or methanol to the electrolyte allows a shift of oxidation potentials in a specific range, creating suitable systems for selective anodic cross-coupling reactions. The shift in the redox potentials depends on the substitution pattern of the substrate employed. The concept has been expanded from arene-phenol to phenol-phenol as well as phenol-aniline cross-coupling. This driving force for selectivity in oxidative coupling might also explain previous findings using HFIP and hypervalent iodine reagents. A remarkable and tunable solvent effect is responsible for the highly selective cross-coupling of phenols with arenes, phenols or aniline derivatives (see scheme). The solvent mixture allows the decoupling of nucleophilicity and oxidation potential to some extent.
About the selectivity and reactivity of active nickel electrodes in C-C coupling reactions
Beil, Sebastian B.,Bomm, Alexander,Breiner, Manuel,Holtkamp, Michael,Karst, Uwe,Müller, Timo,Schüll, Aaron,Schade, Wolfgang,Schollmeyer, Dieter,Schulz, Lara,Waldvogel, Siegfried R.
, p. 14249 - 14253 (2020/04/23)
Active anodes which are operating in highly stable protic media such as 1,1,1,3,3,3-hexafluoroisopropanol are rare. Nickel forms, within this unique solvent, a non-sacrificial active anode at constant current conditions, which is superior to the reported powerful molybdenum system. The reactivity for dehydrogenative coupling reactions of this novel active anode increases when the electrolyte is not stirred during electrolysis. Besides the aryl-aryl coupling, a dehydrogenative arylation reaction of benzylic nitriles was found while stirring the mixture providing quick access to synthetically useful building blocks.
Active Molybdenum-Based Anode for Dehydrogenative Coupling Reactions
Beil, Sebastian B.,Müller, Timo,Sillart, Sydney B.,Franzmann, Peter,Bomm, Alexander,Holtkamp, Michael,Karst, Uwe,Schade, Wolfgang,Waldvogel, Siegfried R.
supporting information, p. 2450 - 2454 (2018/02/09)
A new and powerful active anode system that can be operated in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) has been discovered. In HFIP the molybdenum anode forms a compact, conductive, and electroactive layer of higher-valent molybdenum species. This system can replace powerful but stoichiometrically required MoV reagents for the dehydrogenative coupling of aryls. This electrolytic reaction is more sustainable and allows the conversion of a broad scope of activated arenes.
Mild, Fast, and Easy to Conduct MoCl5-Mediated Dehydrogenative Coupling Reactions in Flow
Beil, Sebastian B.,Uecker, Ise,Franzmann, Peter,Müller, Timo,Waldvogel, Siegfried R.
supporting information, p. 4107 - 4110 (2018/07/15)
A convenient and straightforward approach to performing oxidative coupling reactions in flow is presented. A collection of electron-rich benzene derivatives was subjected to this protocol, and the distinct utility of molybdenum pentachloride (MoCl5) is established. Using this unexplored protocol, biphenyls could be obtained in 21-91% isolated yield. This simple protocol opens a new chapter in reagent-mediated dehydrogenative coupling reactions, and yields are compared to classical approaches.
Aerobic oxidative homocoupling reaction of anilides using heterogeneous metal catalysts
Fujimoto, Shigenobu,Matsumoto, Kenji,Iwata, Takayuki,Shindo, Mitsuru
supporting information, p. 973 - 976 (2017/02/15)
We have developed a heterogeneous catalytic oxidative homocoupling reaction of dimethoxyanilides under an oxygen atmosphere. The resulting homo-dimers are useful for the construction of heterocycles, demonstrating the potential of heterogeneous metal catalysts.
Photocatalytic Phenol–Arene C–C and C–O Cross-Dehydrogenative Coupling
Eisenhofer, Anna,Hioe, Johnny,Gschwind, Ruth M.,K?nig, Burkhard
supporting information, p. 2194 - 2204 (2017/04/24)
Phenol-containing nonsymmetrical biaryls play an important role in natural-product synthesis, as ligands in metal catalysis, and in organic functional materials. Their synthesis through cross-coupling reactions by two-fold direct C–H activation are import
