- Catalytic dioxygen activation by Co(ii) complexes employing a coordinatively versatile ligand scaffold
-
The ligand bis(2-isobutyrylamidophenyl)amine has been prepared and used to stabilize both mononuclear and dinuclear cobalt(ii) complexes. The nuclearity of the cobalt product is regulated by the deprotonation state of the ligand. Both complexes catalytica
- Sharma, Savita K.,May, Philip S.,Jones, Matthew B.,Lense, Sheri,Hardcastle, Kenneth I.,MacBeth, Cora E.
-
-
Read Online
- Preparation method of secondary aromatic amine
-
The invention provides a method for preparing secondary aromatic amine by performing a palladium-catalyzed C-N coupling reaction on (pseudo)aryl halide and (pseudo)heterocyclic aryl halide and primary(heterocyclic)aromatic amine. The method is characterized in that an alkali for promoting the reaction is an alkali metal carboxylate or an alkali metal bicarbonate.
- -
-
Paragraph 0014
(2021/03/31)
-
- A terphenyl phosphine as a highly efficient ligand for palladium-catalysed amination of aryl halides with 1° anilines
-
A terphenyl phosphine ligand (2,6-bis(2,4,6-triisopropylphenyl)phenyl-dicyclohexylphosphine, TXPhos) and its supported palladium complex [(TXPhos)(allyl)PdCl] have been developed and the catalyst system is highly efficient in amination of aryl halides with 1° anilines, especially effective for densely functionalized substrates including both partners possessing ortho-ester, acetyl, nitrile and nitro groups. With the TXPhos-supported catalyst system, many partner combinations have been unprecedentedly realized and the base scope has been even extended to KOAc, which is even the best choice in the amination of 2-nitrochlorobenzene.
- Shi, Ji-cheng,Zhang, Lixue,Zhou, Fabin
-
p. 238 - 243
(2021/09/07)
-
- Round-Trip Oxidative Addition, Ligand Metathesis, and Reductive Elimination in a PIII/PVSynthetic Cycle
-
A synthetic cycle for aryl C-F substitution comprising oxidative addition, ligand metathesis, and reductive elimination at a Cs-symmetric phosphorus triamide (1, P{N[o-NMe-C6H4]2}) is reported. Reaction of 1 with perfluoroarenes (ArF-F) results in C-F oxidative addition, yielding fluorophosphoranes 1·[F][ArF]. The P-fluoro substituent is exchanged for hydride by treatment with DIBAL-H, generating hydridophosphoranes 1·[H][ArF]. Heating of 1·[H][ArF] regenerates 1 by C-H reductive elimination of ArF-H, where experimental and computational studies establish a concerted but highly asynchronous mechanism. The results provide well-characterized examples of the full triad of elementary mechanistic aryl C-X substitution steps at a single main-group site.
- Lim, Soohyun,Radosevich, Alexander T.
-
supporting information
p. 16188 - 16193
(2020/10/26)
-
- Structure, Spectroscopy, and Reactivity of a Mononuclear Copper Hydroxide Complex in Three Molecular Oxidation States
-
Structural, spectroscopic, and reactivity studies are presented for an electron transfer series of copper hydroxide complexes supported by a tridentate redox-active ligand. Single crystal X-ray crystallography shows that the mononuclear [CuOH]1+ core is stabilized via intramolecular H-bonds between the H-donors of the ligand and the hydroxide anion when the ligand is in its trianionic form. This complex undergoes two reversible oxidation processes that produce two metastable "high-valent"CuOH species, which can be generated by addition of stoichiometric amounts of 1e- oxidants. These CuOH species are characterized by an array of spectroscopic techniques including UV-vis absorption, electron paramagnetic resonance (EPR), and X-ray absorption spectroscopies (XAS), which together indicate that all redox couples are ligand-localized. The reactivity of the complexes in their higher oxidation states toward substrates with modest O-H bond dissociation energies (e.g., 4-substitued-2,6-di-tert-butylphenols) indicates that these complexes act as 2H+/2e- oxidants, differing from the 1H+/1e- reactivity of well-studied [CuOH]2+ systems.
- Garcia-Bosch, Isaac,Lancaster, Kyle M.,Macmillan, Samantha N.,Rajabimoghadam, Khashayar,Siegler, Maxime A.,Wu, Tong
-
supporting information
p. 12265 - 12276
(2020/08/06)
-
- A Nontrigonal Tricoordinate Phosphorus Ligand Exhibiting Reversible “Nonspectator” L/X-Switching
-
We report here a “nonspectator” behavior for an unsupported L-function σ3-P ligand (i.e. P{N[o-NMe-C6H4]2}, 1a) in complex with the cyclopentadienyliron dicarbonyl cation (Fp+). Treatment of 1a?Fpsup
- Cleveland, Gregory T.,Radosevich, Alexander T.
-
supporting information
p. 15005 - 15009
(2019/11/05)
-
- Rhodium Complexes Bearing PAlP Pincer Ligands
-
We report rhodium complexes bearing PAlP pincer ligands with an X-type aluminyl moiety. IR spectroscopy and single-crystal X-ray diffraction analysis of a carbonyl complex exhibit the considerable σ-donating ability of the aluminyl ligand, whose Lewis acidity is confirmed through coordination of pyridine to the aluminum center. The X-type PAlP-Rh complexes catalyze C2-selective monoalkylation of pyridine with alkenes.
- Hara, Naofumi,Saito, Teruhiko,Semba, Kazuhiko,Kuriakose, Nishamol,Zheng, Hong,Sakaki, Shigeyoshi,Nakao, Yoshiaki
-
supporting information
p. 7070 - 7073
(2018/06/01)
-
- P-N Cooperative Borane Activation and Catalytic Hydroboration by a Distorted Phosphorous Triamide Platform
-
Studies of the stoichiometric and catalytic reactivity of a geometrically constrained phosphorous triamide 1 with pinacolborane (HBpin) are reported. The addition of HBpin to phosphorous triamide 1 results in cleavage of the B-H bond of pinacolborane through addition across the electrophilic phosphorus and nucleophilic N-methylanilide sites in a cooperative fashion. The kinetics of this process of were investigated by NMR spectroscopy, with the determined overall second-order empirical rate law given by ν = -k[1][HBpin], where k = 4.76 × 10-5 M-1 s-1 at 25 °C. The B-H bond activation process produces P-hydrido-1,3,2-diazaphospholene intermediate 2, which exhibits hydridic reactivity capable of reacting with imines to give phosphorous triamide intermediates, as confirmed by independent synthesis. These phosphorous triamide intermediates are typically short lived, evolving with elimination of the N-borylamine product of imine hydroboration with regeneration of the deformed phosphorous triamide 1. The kinetics of this latter process are shown to be first-order, indicative of a unimolecular mechanism. Consequently, catalytic hydroboration of a variety of imine substrates can be realized with 1 as the catalyst and HBpin as the terminal reagent. A mechanistic proposal implicating a P-N cooperative mechanism for catalysis that incorporates the various independently verified stoichiometric steps is presented, and a comparison to related phosphorus-based systems is offered.
- Lin, Yi-Chun,Hatzakis, Emmanuel,McCarthy, Sean M.,Reichl, Kyle D.,Lai, Ting-Yi,Yennawar, Hemant P.,Radosevich, Alexander T.
-
supporting information
p. 6008 - 6016
(2017/05/04)
-
- CuSO4-mediated decarboxylative C-N cross-coupling of aromatic carboxylic acids with amides and anilines
-
CuSO4-mediated decarboxylative C-N cross-coupling of aromatic carboxylic acid with amide has been developed, leading to N-arylamides in modest to excellent yields. Anilines bearing electron-withdrawing substituents could also couple efficiently
- Sheng, Wei-Jian,Ye, Qing,Yu, Wu-Bin,Liu, Ren-Rong,Xu, Meng,Gao, Jian-Rong,Jia, Yi-Xia
-
supporting information
p. 599 - 601
(2015/02/19)
-
- Reversible intermolecular E-H oxidative addition to a geometrically deformed and structurally dynamic phosphorous triamide
-
The synthesis and reactivity of geometrically constrained tricoordinate phosphorus (σ3-P) compounds supported by tridentate triamide chelates (N[o-NR-C6H4]23-; R = Me or iPr) are reported.
- Zhao, Wei,McCarthy, Sean M.,Lai, Ting Yi,Yennawar, Hemant P.,Radosevich, Alexander T.
-
supporting information
p. 17634 - 17644
(2015/02/02)
-
- Tuning the electronic and steric parameters of a redox-active tris(amido) ligand
-
A family of tantalum compounds was prepared to probe the electronic effects engendered by the addition of electron-donating or electron-withdrawing groups to the 4/4′ positions of the redox-active ligand derived from bis(2-isopropylamino-4-X-phenyl)amine
- Munha, Rui F.,Zarkesh, Ryan A.,Heyduk, Alan F.
-
p. 11244 - 11255
(2013/10/22)
-
- A structure-activity study of Ni-catalyzed alkyl-alkyl kumada coupling. Improved catalysts for coupling of secondary alkyl halides
-
A structureactivity study was carried out for Ni catalyzed alkylalkyl Kumada-type cross coupling reactions. A series of new nickel(II) complexes including those with tridentate pincer bis(amino)amide ligands (RN2N) and those with bidentate mixed amino-amide ligands (RNN) were synthesized and structurally characterized. The coordination geometries of these complexes range from square planar, tetrahedral, to square pyramidal. The complexes had been examined as precatalysts for cross coupling of nonactivated alkyl halides, particularly secondary alkyl iodides, with alkyl Grignard reagents. Comparison was made to the results obtained with the previously reported Ni pincer complex [( MeN2N)NiCl]. A transmetalation site in the precatalysts is necessary for the catalysis. The coordination geometries and spin-states of the precatalysts have a small or no influence. The work led to the discovery of several well-defined Ni catalysts that are significantly more active and efficient than the pincer complex [(MeN2N)NiCl] for the coupling of secondary alkyl halides. The best two catalysts are [(HNN)Ni(PPh3)Cl] and [(HNN)Ni(2,4-lutidine)Cl]. The improved activity and efficiency was attributed to the fact that phosphine and lutidine ligands in these complexes can dissociate from the Ni center during catalysis. The activation of alkyl halides was shown to proceed via a radical mechanism.
- Ren, Peng,Vechorkin, Oleg,Von Allmen, Kim,Scopelliti, Rosario,Hu, Xile
-
supporting information; experimental part
p. 7084 - 7095
(2011/06/26)
-
- Supramolecular Scaffolds and Methods of Making the Same
-
Tribenzo-1,4,7-triazacyclononane and derivatives thereof having a formula (I) are disclosed. Methods of making tribenzo-1,4,7-triazacyclononane and related compounds also are disclosed.
- -
-
Page/Page column 12
(2010/03/04)
-
- Efficient methods for the synthesis of 2-hydroxyphenazine based on the Pd-catalyzed N-arylation of aryl bromides
-
(Chemical Equation Presented) Substituted diphenylamines can be synthesized by Pd(0)-catalyzed N-arylation using o-nitroanilines and nitro-substituted aryl bromides for a substrate. Cyclization of the diphenylamines by various methods, including the intramolecular Pd(0)-catalyzed N-arylation, produces 2-methoxyphenazine which can easily be deprotected to give 2-hydroxyphenazine. This phenazine is required to synthesize methanophenazine, a novel redoxactive cofactor isolated from methanogenic archaea.
- Tietze, Mario,Iglesias, Alberto,Merisor, Elena,Conrad, Juergen,Klaiber, Iris,Beifuss, Uwe
-
p. 1549 - 1552
(2007/10/03)
-
- Palladium-catalyzed arylation of ureas
-
Urea arylation with aryl halides in the presence of catalyst precursor Pd2dba3-CHCl3/Xantphos and Cs 2CO3 in dioxane at 100°C affords symmetrical N,N′-diarylureas in 64-92% yield. With the same cataly
- Artamkina,Sergeev,Beletskaya
-
p. 538 - 545
(2007/10/03)
-
- Palladium-catalyzed reaction of aryl halides with ureas
-
A new method for the palladium-catalyzed arylation of ureas is described. The coupling reaction of urea and phenylurea with aryl halides containing electron-withdrawing groups in the p-position in dioxane in the presence of 0.5-1.0 mol% of Pd2dba3·CHCl3, Xantphos and Cs2CO3 as a base gives N,N′-diarylureas in yields of 64-92%.
- Artamkina, Galina A.,Sergeev, Alexey G.,Beletskaya, Irina P.
-
p. 4381 - 4384
(2007/10/03)
-
- Aprotic diazotization in the presence of cuprous cyanide
-
In a procedure of extreme simplicity and rapidity a mixture of an aromatic primary amine, copper (I) cyanide and an alkyl nitrite in dimethyl sulphoxide yielded fair to moderate yields of the corresponding nitriles. Side processes observed were reduction (NH2&[H), nitration (NH2←NO2) and hydroxylation (NH2&[OH). In the case of polyhaloanilines halogen dance products could be detected.
- Giumanini, Angelo G.,Verardo, Giancarlo,Geatti, Paola,Strazzolini, Paolo
-
p. 7137 - 7148
(2007/10/03)
-
- Aromatic Nitro group Displacement Reactions. Part 2. The Synthesis of Diarylamines and some Heteroaromatic Analogues.
-
In dipolar aprotic solvents, activated aromatic nitro-groups can usually be displaced by anilines of enhanced N-acidity in the presence of the heavier alkali-metal carbonates.When catalysed by potassium t-butoxide, however, attack occurs preferentially at other reactive centers in the molecule, except where the nitro-group is highly activated.Some of the resulting diarylamines (the term is here expanded to include arylaminoxanthen-9-ones) are intermediates in the synthesis of heterocycles.
- Gorvin, John H.
-
p. 1662 - 1681
(2007/10/02)
-
- The Synthesis of Di- and Tri-arylamines through Halogen Displacement by Base-activated Arylamines: Comparison with the Ullmann Condensation
-
In dipolar aprotic solvents, nitranions derived from anilines of enhanced N-acidity displace fluorine from activated aromatic compounds at room temperature.Diarylamines thus produced are free from triarylamines, which are formed at higher temperatures when diarylamines, after N-deprotonation by potassium t-butoxyde or by the heavier alkali metal carbonates, similarly displace activated fluorine.Certain diarylamines can also be prepared by chlorine displacement in the presence of alkali metal carbonates.It is confirmed that such carbonates play only an auxiliary role in the Ullmann (copper-assisted) diarylamine synthesis conducted in dipolar aprotic solvents; they may indeed impede the reaction in some instances.
- Gorvin, John H.
-
p. 1331 - 1336
(2007/10/02)
-
- The Reduction of Some 2,2'-Dinitrodiaryl Compounds and Related Compounds by Thiourea S,S-Dioxide (Formamidinesulfinic Acid)
-
The reaction of thiourea S,S-dioxide (formamidinesulfinic acid) in ethanolic alkali with 2,2'-dinitrobiphenyl and several related dinitro compounds possessing an-X-bridge (where X = NH, NMe, O and S), located at the 1,1'-positions, has been investigated.With 2,2'-dinitrobiphenyl (which gives good yields of benzocinnoline and its oxides) and, to a minor extent, with 2,2'-dinitrodiphenylamine, an intramolecular reaction occured to give heterocyclic products; with each of the other dinitro compounds, the only product obtained was formed as the result of a Smiles rearrangement.
- Wilshire, John F. K.
-
p. 995 - 1001
(2007/10/02)
-
- Photolysis of N-Nitrosodiphenylamines and N-Nitrosocarbazole
-
N-Nitrosodiphenylamine, N-nitroso-2-nitrodiphenylamine and N-nitrosocarbazole on irradiation in benzene give products resulting from nitroso group migration.
- Sharma, K. S.,Kumari, Sharda,Goel, Vijender Kumar
-
p. 435 - 436
(2007/10/02)
-
- ELECTROCHEMICAL REDUCTION OF 2,2'-DINITRODIPHENYL ETHER AND 2,2'-DINITRODIPHENYLAMINE AT MERCURY CATHODES
-
2,2'-Dinitrodiphenyl ether (I) is reduced at less negative potentials than 2,2'-dinitrodiphenylamine (II); the respective mechanisms of their reduction differ essentially. (I) is electrolytically reduced in a single wave with an uptake of eight electrons per molecule, giving rise to a bishydroxylamine intermediate which undergoes an intramolecular disproportionation.The resulting 2-nitroso-2'-amino-diphenyl ether undergoes a chemical follow-up reaction leading on the one hand to dibenzo--(1,4,5)-oxadiazepine, on the other hand to a diphenylamine product (resulting by a chemical rearrangement) which reacts with reductants present in the solution and yields dihydrophenazine.It is merely by chance that in the electrolytical reduction of II dihydrophenazine also results in addition to other products. 2,2'-dinitrodiphenylamine (II) enables here, however, a partial electrolytical reduction in which 2-amino-2'-nitrodiphenylamine is formed in a single 6-electron wave.In the following, more negative wave, is clearly separated only in alkaline media, the other nitro group reduces with an uptake of 4 electrons to an intermediate which eliminates the hydroxylamine group with the corresponding electron pair.The subsequent chemical reaction leads to dihydrophenazine.This substance is the reduced form of an chemically and electrochemically reversible system, this system participates in the chemical reaction of reaction intermediates.Its regeneration readily proceeds at potentials more positive than the reduction potential of II.Phenazine is oxidized in the catholyte by the hydroxylamine set free to phenazine N-oxide.Nitrogen is thus eliminated in its elemental form via hydroxylamine from the substrate molecule.
- Hlavaty, Jaromir,Volke, Jiri,Bakos, Viktor
-
p. 379 - 393
(2007/10/02)
-