- Transition metal-free, visible-light mediated synthesis of 1,10-phenanthroline derived ligand systems
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A broad range of 1,10-phenanthroline substrates was efficiently C-H functionalised, providing rapid, gram-scale access to substituted heteroaromatic cores of broad utility. Furthermore, this C-H functionalisation pathway was extended to the synthesis of previously inaccessible, ultra-soluble, 2,9-bis-triazinyl-1,10-phenanthroline (BTPhen) ligands for advanced nuclear fuel cycles.
- Edwards, Alyn C.,Geist, Andreas,Müllich, Udo,Sharrad, Clint A.,Pritchard, Robin G.,Whitehead, Roger C.,Harwood, Laurence M.
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- Chemoselective Catalytic α-Oxidation of Carboxylic Acids: Iron/Alkali Metal Cooperative Redox Active Catalysis
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We developed a chemoselective catalytic activation of carboxylic acid for a 1e- radical process. α-Oxidation of a variety of carboxylic acids, which preferentially undergo undesired decarboxylation under radical conditions, proceeded efficiently under the optimized conditions. Chemoselective enolization of carboxylic acid was also achieved even in the presence of more acidic carbonyls. Extensive mechanistic studies revealed that the cooperative actions of iron species and alkali metal ions derived from 4 ? molecular sieves substantially facilitated the enolization. For the first time, catalytic enolization of unprotected carboxylic acid was achieved without external addition of stoichiometric amounts of Br?nsted base. The formed redox-active heterobimetallic enediolate efficiently coupled with free radical TEMPO, providing synthetically useful α-hydroxy and keto acid derivatives.
- Tanaka, Tsukushi,Yazaki, Ryo,Ohshima, Takashi
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supporting information
p. 4517 - 4524
(2020/03/05)
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- Palladium-Catalyzed Intramolecular Cyclization of Nitroalkenes: Synthesis of Thienopyrroles
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In the presence of carbon monoxide, the palladium/phenanthroline system catalyzes the intramolecular amination of thiophene rings following the reduction of a nitroalkene moiety directly attached to the S-heterocyclic ring. Optimization of the ligand and reaction conditions allowed the synthesis of a series of thienopyrroles aryl/alkyl-substituted at either the 2- or 3-position of the pyrrole ring. By using low pressures of carbon monoxide (5 bars), high yields of fused bicyclic compounds have been obtained (up to 98 % yield).
- El-Atawy, Mohamed A.,Ferretti, Francesco,Ragaini, Fabio
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supporting information
p. 1902 - 1910
(2017/04/21)
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- On Ni catalysts for catalytic, asymmetric Ni/Cr-mediated coupling reactions
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The importance of the Ni catalyst in achieving catalytic asymmetric Ni/Cr-mediated coupling reactions effectively is demonstrated. Six phenanthroline-NiCl2 complexes 1a-c and 2a-c and five types of alkenyl iodides A-E were chosen for the study, thereby demonstrating that these Ni catalysts display a wide range of overall reactivity profiles in terms of the degree of asymmetric induction, geometrical isomerization, and coupling rate. For three types of alkenyl iodides A-C, a satisfactory Ni catalyst(s) was found within 1a-c and 2a-c. For disubstituted (Z)-alkenyl iodide D, 2c was identified as an acceptable Ni catalyst in terms of the absence of Z → E isomerization and the degree of asymmetric induction but not in terms of the coupling rate. Two phosphine-based Ni catalysts, [(Me)3P]2· NiCl2 and [(cy)3P]2·NiCl2, were found to meet all three criteria for D. The bond-forming reaction at the C16-C17 position of palytoxin was used to demonstrate the usefulness of the Ni catalysts thus identified.
- Liu, Xiang,Li, Xiaoyong,Chen, Yu,Hu, Yimin,Kishi, Yoshito
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supporting information; experimental part
p. 6136 - 6139
(2012/05/07)
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- Copper-catalyzed N-arylation of imidazoles and benzimidazoles
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(Chemical Equation Presented) 4,7-Dimethoxy-1,10-phenanthroline (L1c) was found to be an efficient ligand for the copper-catalyzed N-arylation of imidazoles and benzimidazoles with both aryl iodides and bromides under mild conditions. Further optimization of the system has revealed that the addition of poly(ethylene glycol) accelerates this reaction. A variety of hindered and functionalized imidazoles, benzimidazoles, and aryl halides were transformed in good to excellent yields. Heteroaryl halides were also coupled in moderate to good yields. We also present the results obtained from a series of coupling reactions, which directly compare the use of L1c with other recently reported ligands.
- Altman, Ryan A.,Koval, Erica D.,Buchwald, Stephen L.
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p. 6190 - 6199
(2008/02/10)
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- 4,7-Dimethoxy-1,10-phenanthroline: An excellent ligand for the Cu-catalyzed N-arylation of imidazoles
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4,7-Dimethoxy-1,10-phenanthroline (L) was found to be an efficient ligand for the copper-catalyzed N-arylation of imidazole with aryl iodides and bromides under mild conditions. A variety of hindered and functionalized imidazoles and aryl halides were transformed in good to excellent yields.
- Altman, Ryan A.,Buchwald, Stephen L.
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p. 2779 - 2782
(2007/10/03)
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- Tris(1,10-phenanthroline)iron(II) Complexes. Influence of 4,7-Donor Substitution on the Redox Potential
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Several new 4,7-donor substituted 1,1-phenanthrolines were synthesized and the corresponding tris(1,10-phenanthroline)iron(II) complexes were studied by cyclic voltammetry.All iron(II) complexes showed fully reversible waves at scan rates between 50 and 500 mV/s.For some redox systems the kinetics in their reaction with chlorine was studied.Complexes 7k and 7l significantly extent the potential range of tris(1,10-phenanthroline)iron(II) complexes. - Keywords: Redox Potential, Cyclic Voltammetry, Electron Transfer, Kinetics with Chlorine
- Levis, Michael,Luening, Ulrich,Mueller, Michael,Schmittel, Michael,Woehrle, Clemens
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p. 675 - 682
(2007/10/02)
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