- High turnover number and rapid, room-temperature amination of chloroarenes using saturated carbene ligands
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Pd(dba)2, 0.02-2 mol% Ligand 1, 0.08-2 mol% ArCl + NHRR′ → Ar-NRR′ NaO-t Bu, DME Ar = unactivated aryl, rt-100°C (71%-quant.) heteroaryl NHRR′ = 1° and 2° aryl; 2° acyclic and cyclic alkyl; imino A catalytic system for the mild amination of aryl chlorides is described. This system consists of a Pd(0) precursor and a dihydroimidazoline carbene ligand, which is generated in situ from its protonated tetrafluoroborate salt (2). Using this catalyst, aryl and heteroaryl chlorides react with secondary amines and anilines within hours at room temperature. Turnover numbers as high as 5000 are obtained at elevated temperatures for reaction of morpholine with an unactivated aryl chloride.
- Stauffer, Shaun R.,Lee, Sunwoo,Stambuli, James P.,Hauck, Sheila I.,Hartwig, John F.
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- Copper-Catalysed Electrophilic Amination of Aryl(alkenyl) Boronic Acids with Nitrogen-Containing Hypervalent Iodine (III) Reagent
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A copper-catalysed electrophilic N-imination of aryl(alkenyl) boronic acids with a stable hypervalent iodine(III) reagent containing a transferable (diarylmethylene)amino group is developed. The electrophilic C?N cross-coupling reaction proceeds smoothly at room temperature under oxidant-free and base-free conditions, which is further characterized by the broad functional group compatibility, thereof, extending the N-electrophile scope of electrophilic C?N cross-coupling outside the limitation of N?O and N?Cl reagents. (Figure presented.).
- Hu, Yuanyuan,Zheng, Songlin,Fan, Wu,Yuan, Weiming
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supporting information
p. 4701 - 4707
(2021/08/23)
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- Catalytic Imido-Transfer Reactions of Well-Defined Silica-Supported Titanium Imido Complexes Prepared via Surface Organometallic Chemistry
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We expand the series of well-defined silica-supported titanium imido complexes of general formula (SiO)Ti(═NtBu)X(py)n prepared via surface organometallic chemistry in order to analyze the effect of the X ligand on their catalytic properties. Two new surface complexes, (SiO)Ti(═NtBu)Cl(py)2 (2s) and (SiO)Ti(═NtBu)Cp(py) (3s), have been prepared and characterized with physicochemical techniques, and their performance in oxo/imido heterometathesis and other catalytic imido-transfer reactions has been studied and compared to that of the previously reported catalyst (SiO)Ti(═NtBu)(Me2Pyr)(py)2 (1s; Me2Pyr = 2,5-dimethylpyrrolyl).
- Zhizhko, Pavel A.,Pichugov, Andrey V.,Bushkov, Nikolai S.,Rumyantsev, Andrey V.,Utegenov, Kamil I.,Talanova, Valeria N.,Strelkova, Tatyana V.,Lebedev, Dmitry,Mance, Deni,Zarubin, Dmitry N.
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p. 1014 - 1023
(2020/02/26)
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- An expedient one-pot synthesis of benzophenone Schiff bases from benzene
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A simple and efficient one-pot synthesis of benzophenone Schiff bases from benzene, CCl4 and aromatic amines was developed based on the the reaction of benzene with CCl4·AlCl3 complex. This method affords Ph2CCl2 as well as the products of its subsequent reaction with aromatic amines, benzophenone Schiff bases, selectively and in good yields.
- Akhrem, Irena S.,Afanas'eva, Lyudmila V.,Avetisyan, Dzhul'etta V.,Artyushin, Oleg I.,Kagramanov, Nikolai D.
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p. 238 - 240
(2020/05/25)
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- Palladium-Catalyzed Diarylation of Isocyanides with Tetraarylleads for the Selective Synthesis of Imines and α-Diimines
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Using tetraaryllead compounds (PbAr4) as arylating reagents, isocyanides undergo selective diarylation in the presence of palladium catalysts such as Pd(OAc)2 or Pd(PPh3)4 to afford imines and/or α-diimines based on the isocyanide employed. With aliphatic isocyanides, imines are obtained preferentially, whereas α-diimines are formed in the case of electron-rich aromatic isocyanides. The differences in imine/α-diimine selectivity can be attributed to the stability of imidoylpalladium intermediates formed in this catalytic reaction. Compared with other arylating reagents, tetraaryllead compounds are excellent candidates for use in the selective transformations to imines and/or α-diimines, especially in terms of inhibiting the oligomerization of isocyanides, which results in a lower product selectivity in many transition-metal-catalyzed reactions of isocyanides.
- Tran, Cong Chi,Kawaguchi, Shin-Ichi,Kobiki, Yohsuke,Matsubara, Hitomi,Tran, Dat Phuc,Kodama, Shintaro,Nomoto, Akihiro,Ogawa, Akiya
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p. 11741 - 11751
(2019/10/02)
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- Oxidative Rearrangement of Primary Amines Using PhI(OAc)2 and Cs2CO3
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An oxidative rearrangement of primary amines mediated by a hypervalent iodine(III) reagent is herein reported. The combination of PhI(OAc)2 and Cs2CO3 proves highly efficient at inducing the direct 1,2-C to N migration of primary amines, which can be applied to the preparation of both acyclic and cyclic amines. A mechanistic study shows that the rearrangement proceeds via a concerted mechanism.
- Yamakoshi, Wataru,Arisawa, Mitsuhiro,Murai, Kenichi
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supporting information
(2019/05/08)
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- Catalytic Oxo/Imido Heterometathesis by a Well-Defined Silica-Supported Titanium Imido Complex
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Grafting Ti(=NtBu)(Me2Pyr)2(py)2 (Me2Pyr= 2,5-dimethylpyrrolyl, py=pyridine) onto the surface of silica partially dehydroxylated at 700 °C gives the well-defined silica-supported Ti imido complex (≡SiO)Ti(=NtBu)(Me2Pyr)(py)2, which is fully characterized by IR and solid-state NMR spectroscopy as well as elemental and mass balance analyses. While stoichiometric imido-transfer reactivity is typical for Ti imides, the obtained surface complex is unique in that it enables catalytic transformations involving Ti imido and oxo intermediates. In particular, it efficiently catalyzes imidation of carbonyl compounds with N-sulfinylamines by oxo/imido heterometathesis.
- Zhizhko, Pavel A.,Pichugov, Andrey V.,Bushkov, Nikolai S.,Allouche, Florian,Zhizhin, Anton A.,Zarubin, Dmitry N.,Ustynyuk, Nikolai A.
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supporting information
p. 10879 - 10882
(2018/07/31)
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- Photocatalytic and Chemoselective Transfer Hydrogenation of Diarylimines in Batch and Continuous Flow
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A visible-light photocalytic method for the chemoselective transfer hydrogenation of imines in batch and continuous flow is described. The reaction utilizes Et3N as both hydrogen source and single-electron donor, enabling the selective reduction of imines derived from diarylketimines containing other reducible functional groups including nitriles, halides, esters, and ketones. The dual role of Et3N was confirmed by fluorescence quenching measurements, transient absorption spectroscopy, and deuterium-labeling studies. Continuous-flow processing facilitates straightforward scale-up of the reaction.
- Van As, Dean J.,Connell, Timothy U.,Brzozowski, Martin,Scully, Andrew D.,Polyzos, Anastasios
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supporting information
p. 905 - 908
(2018/02/22)
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- Generation and selected reactions of chlorinated thiocarbonyl S-imides*
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N-Aryl-1,1,1-trichloromethanesulfenamides ArNH-SCCl3 easily undergo dehydrochlorination upon treatment with potassium hydroxide in ethanolic solution. The intermediate thiocarbonyl S-imides formed thereby behave differently depending on the typ
- Mlostoń, Grzegorz,Pipiak, Paulina,Voss, Jürgen,Buddensiek, Dirk,Senning, Alexander
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p. 530 - 547
(2017/09/27)
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- An Air-Stable Nickel(0) Phosphite Precatalyst for Primary Alkylamine C-N Cross-Coupling Reactions
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In this report we describe the design and preparation of a new air-stable nickel phosphite based catalyst for unique C-N bond forming processes. Specifically, (BINAP)Ni[P(OPh)3]2, is presented as an effective catalyst for a range of amination reactions between aryl halides and primary alkylamines. The results are supported by relevant kinetic studies, DFT calculations and a catalytic cycle indicating possible reaction intermediates. The amination reaction between a series of aryl halides and primary alkylamines is described using a new air-stable nickel phosphite based catalyst (BINAP)Ni[P(OPh)3]2.
- Kampmann, Sven S.,Skelton, Brian W.,Wild, Duncan A.,Koutsantonis, George A.,Stewart, Scott G.
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supporting information
p. 5995 - 6004
(2015/09/22)
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- Oxo/Imido heterometathesis reactions catalyzed by a silica-supported tantalum imido complex
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Grafting Ta(=NtBu)(CH2CMe2Ph)3 onto the surface of silica partially dehydroxylated at 300°C leads to the formation of the surface imido complex (≡SiO)2Ta(=N tBu)(CH2CMe2Ph) as a major species, which was characterized with EXAFS, 13C CP/MAS NMR, diffuse reflectance FTIR, elemental analyses, and chemical reactivity. The obtained material acts as an efficient heterogeneous catalyst for various oxo/imido heterometathesis transformations: imidation of ketones and DMF with N-sulfinylamines and condensation of N-sulfinylamines into sulfurdiimines and phenyl isocyanate into diphenylcarbodiimide.
- Zhizhko, Pavel A.,Zhizhin, Anton A.,Belyakova, Olga A.,Zubavichus, Yan V.,Kolyagin, Yuriy G.,Zarubin, Dmitry N.,Ustynyuk, Nikolai A.
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supporting information
p. 3611 - 3617
(2013/07/26)
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- Cu(OAc)2-mediated cross-coupling reaction of benzophenone N,N,N-trimethylhydrazonium salts and aryl boronic acids
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Cu(OAc)2-mediated coupling of benzophenone N,N,N- trimethylhydrazonium salts and aryl boronic acids proceeded to afford N-aryl imines.
- Kitamura, Mitsuru,Tokuda, Yu,Tashiro, Norifumi,Okauchi, Tatsuo
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p. 1687 - 1690
(2013/03/13)
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- Buchwald-Hartwig amination of (hetero)aryl chlorides by employing Mor-DalPhos under aqueous and solvent-free conditions
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We report on the application of the [Pd(cinnamyl)Cl]2/Mor- DalPhos catalyst system in the Buchwald-Hartwig amination of (hetero)aryl chlorides with primary or secondary amines conducted either under aqueous conditions without the use of co-solvents and/or surfactants or under solvent-free conditions (52 examples). We have established that reactions of this type can be conducted without the rigorous exclusion of air, and in the case of the solvent-free reactions, we have demonstrated that appropriately selected liquid and solid reagents can be employed successfully.
- Tardiff, Bennett J.,Stradiotto, Mark
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supporting information; experimental part
p. 3972 - 3977
(2012/08/27)
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- Rational and predictable chemoselective synthesis of oligoamines via Buchwald-Hartwig amination of (hetero)aryl chlorides employing Mor-Dalphos
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We report a diverse demonstration of synthetically useful chemoselectivity in the synthesis of di-, tri-, and tetraamines (62 examples) by use of Buchwald-Hartwig amination employing a single catalyst system ([Pd(cinnamyl)Cl]2/L1; L1 = N-(2-(di(1-adamantyl)phosphino)phenyl) morpholine, Mor-DalPhos). Competition reactions established the following relative preference of this catalyst system for amine coupling partners: linear primary alkylamines and imines > unhindered electron-rich primary anilines, primary hydrazones, N,N-dialkylhydrazines, and cyclic primary alkylamines > unhindered electron-deficient primary anilines, α-branched acyclic primary alkylamines, hindered electron-rich primary anilines ? cyclic and acyclic secondary dialkylamines, secondary alkyl/aryl and diarylamines, α,α-branched primary alkylamines, and primary amides. The new isomeric ligand N-(4-(di(1-adamantyl)phosphino)phenyl)morpholine (p-Mor-DalPhos, L2) was prepared in 63% yield and was crystallographically characterized; the [Pd(cinnamyl)Cl]2/L2 catalyst system exhibited divergent reactivity. Application of the reactivity trends established for [Pd(cinnamyl)Cl] 2/L1 toward the chemoselective synthesis of di-, tri-, and tetraamines was achieved. Preferential arylation was observed at the primary alkylamine position within 2-(4-aminophenyl)ethylamine with [Pd(cinnamyl)Cl] 2/L1 and 4-chlorotoluene (affording 5a); the alternative regioisomer (5a′) was obtained when using [Pd(cinnamyl)Cl]2/L2. These observations are in keeping with coordination chemistry studies, whereby binding of 2-(4-aminophenyl)ethylamine to the in situ generated [(L1)Pd(p-tolyl)] + fragment occurred via the primary amine moiety, affording the crystallographically characterized adduct [(L1)Pd(p-tolyl)(NH2CH 2CH2(4-C6H4NH2)] +OTf- (7) in 72% yield.
- Tardiff, Bennett J.,McDonald, Robert,Ferguson, Michael J.,Stradiotto, Mark
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experimental part
p. 1056 - 1071
(2012/02/15)
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- Silver-mediated C-H activation: Oxidative coupling/cyclization of N -arylimines and alkynes for the synthesis of quinolines
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A silver-mediated tandem protocol for the synthesis of quinolines involving the oxidative coupling/cyclization of N-arylimines and alkynes has been developed. We demonstrated that scenario-dependent metalation could occur either at the ortho C-H bond of an N-arylimine through protonation-driven enhancement of acidity or at the terminal C-H bond of an alkyne by virtue of the carbophilic π-acidity of silver. The diverse set of mechanistic manifolds implemented with a single type of experimental protocol points toward the importance of stringent reactivity analysis of each individual potentially reactive molecular site. Importantly, the direct arene C-H bond activation provides a unique and distinct mechanistic handle for the expansion of reactivity paradigms for silver. As expected, the protocol allows for the incorporation of both internal and terminal alkynes into the products, and in addition, both electron-withdrawing and -donating groups are tolerated on N-arylimines, thus enabling the vast expansion of substituent architectures on quinoline framework. Further, an intriguing phenomenon of structural isomerization and chemical bond cleavage has been observed for aliphatic internal alkynes.
- Zhang, Xu,Liu, Baoqing,Shu, Xin,Gao, Yang,Lv, Haipeng,Zhu, Jin
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supporting information; experimental part
p. 501 - 510
(2012/03/08)
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- Hydride, hydrogen, proton, and electron affinities of imines and their reaction intermediates in acetonitrile and construction of thermodynamic characteristic graphs (TCGs) of imines as a molecule ID card
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(Chemical Equation Presented) A series of 61 imines with various typical structures were synthesized, and the thermodynamic affinities (defined as enthalpy changes or redox potentials in this work) of the imines to abstract hydride anions, hydrogen atoms, and electrons, the thermodynamic affinities of the radical anions of the imines to abstract hydrogen atoms and protons, and the thermodynamic affinities of the hydrogen adducts of the imines to abstract electrons in acetonitrile were determined by using titration calorimetry and electrochemical methods. The pure heterolytic and homolytic dissociation energies of the C=N π-bond in the imines were estimated. The polarity of the C=N double bond in the imines was examined using a linear free-energy relationship. The idea of a thermodynamic characteristic graph (TCG) of imines as an efficient Molecule ID Card was introduced. The TCG can be used to quantitatively diagnose and predict the characteristic chemical properties of imines and their various reaction intermediates as well as the reduction mechanism of the imines. The information disclosed in this work could not only supply a gap of thermodynamics for the chemistry of imines but also strongly promote the fast development of the applications of imines. 2009 American Chemical Society.
- Zhu, Xiao-Qing,Liu, Qiao-Yun,Chen, Qiang,Mei, Lian-Rui
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scheme or table
p. 789 - 808
(2010/04/29)
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- Trans-spanned palladium catalyst for mild and efficient amination of aryl halides with benzophenone imine
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A new protocol for palladium-catalyzed Buchwald-Hartwig amination of aryl chlorides and bromides with benzophenone imine as ammonia surrogate is described. The suggested reaction conditions are mild and may therefore be applied to a variety of sensitive starting materials. Georg Thieme Verlag Stuttgart.
- Grossman, Olga,Rueck-Braun, Karola,Gelman, Dmitri
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p. 537 - 542
(2008/12/21)
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- Base-induced rearrangement of tritylamines to imines: discovery and investigation of the mechanism
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An unexpected compound, the aniline derived benzophenone imine, was isolated when tritylamine was treated with n-BuLi and alkyl halides, during the formation of N-alkyl tritylamines, in the process of preparing primary amines. A nucleophilic attack of the nitrogen anion of tritylamide on the adjacent C-bonded phenyl, either substituted or not, involving a bridging anionic intermediate, is proposed for this base-induced tritylamine rearrangement to produce the corresponding imine. Electron-withdrawing groups in the aromatic ring, favoring the negative charge development, affect the relative migratory tendencies.
- Theodorou, Vassiliki,Skobridis, Konstantinos,Karkatsoulis, Aris
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p. 4284 - 4289
(2007/10/03)
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- N-substituted imines by the copper-catalyzed N-imination of boronic acids and organostannanes with O-acyl ketoximes
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Catalytic quantities of copper(I) or copper(II) sources catalyze the N-imination of boronic acids and organostannanes through reaction with oxime O-carboxylates under nonbasic conditions. This method tolerates various functional groups and takes place efficiently using aryl, heteroaryl, and alkenyl boronic acids and stannanes.
- Liu, Songbai,Yu, Ying,Liebeskind, Lanny S.
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p. 1947 - 1950
(2008/02/02)
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- Amination reactions of aryl halides with nitrogen-containing reagents mediated by palladium/imidazolium salt systems
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Nucleophilic N-heterocyclic carbenes have been conveniently used as catalyst modifiers in amination reactions involving aryl chlorides, aryl bromides, and aryl iodides with various nitrogen-containing substrates. The scope of a coupling process using a Pd(0) or Pd(II) source and an imidazolium salt in the presence of a base, KOtBu or NaOH, was tested using various substrates. The Pd2(dba)3/IPr·HCl (1, IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) system presents the highest activity with respect to electron-neutral and electron-rich aryl chlorides. The ligand is also effective for the synthesis of benzophenone imines, which can be easily converted to the corresponding primary amines by acid hydrolysis. Less reactive indoles were converted to N-aryl-substituted indoles using as supporting ligand the more donating SIPr·HCl (5, SIPr = 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene). The Pd(OAc)2/SIPr·HCl/NaOH system is efficient for the N-arylation of diverse indoles with aryl bromides. The general protocol developed has been applied successfully to the synthesis of a key intermediate in the synthesis of an important new antibiotic. Mechanistically, palladium-to-ligand ratio studies strongly support an active species bearing one nucleophilic carbene ligand.
- Grasa,Viciu,Huang,Nolan
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p. 7729 - 7737
(2007/10/03)
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- Unexpected reactivity of two-coordinate palladium-carbene complexes; synthetic and catalytic implications
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Ligand exchange reactions reveal unexpected lability of the carbene ligands in two coordinate palladium(0) N-heterocyclic carbene complexes; the latter are found to be very effective catalysts for amination of aryl chlorides.
- Titcomb,Caddick,Geoffrey,Cloke,Wilson,McKerrecher
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p. 1388 - 1389
(2007/10/03)
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- Oxidative rearrangement of imines to formamides using sodium perborate
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Oxidation of C-aryl or alkyl-N-arylaldimines 6 or 20 by sodium perborate tetrahydrate (SPB) in trifluoroacetic acid solution gives rearranged N,N-disubstituted formamides 9 and 21. Yields are variable and solvent dependant with the best yields (50-60%) being obtained for electronically neutral C-aryl substituents or C-s-alkyl substituents. Product formation is rationalised in terms of an intermediate oxaziridine 5 that rearranges via acid catalysed O-N bond cleavage. An alternative C-O bond cleavage of these intermediates accounts for the formation of aldehydes, which are common by products. Rearrangement appears to be favoured by N-aryl substituents and by C-substituents that do not stabilise a developing positive charge on carbon. Further support for an oxaziridine intermediate 5 is provided by the observation that MCPBA oxidation of benzaldehyde phenylimine gives rearranged N,N-diphenylformamide. Under the conditions of the SPB oxidative rearrangements, oxaziridine formation may well occur by initial formation of trifluoroperacetic acid. Stereochemical aspects of this novel rearrangement of aldimines 1 → 2 have been investigated using trans- and cis-myrtanal 25 and 30. The observed epimerisation using die N-4-tolyl imine of trans-myrtanal 26 is believed to arise from equilibration of the precursor imine 26 with the tautomeric enamine 35b.
- Nongkunsarn, Pakawan,Ramsden, Christopher A.
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p. 3805 - 3830
(2007/10/03)
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- SYNTHESIS OF KETIMINES VIA PALLADIUM COMPLEX-CATALYZED CROSS-COUPLING OF IMIDOYL CHLORIDES WITH ORGANOTIN COMPOUNDS
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Imidoyl chlorides were successfully transformed into ketimines when treated with organotin compounds in the presence of palladium complex catalysts.
- Kobayashi, Toshi-aki,Sakakura, Toshiyasu,Tanaka, Masato
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p. 3463 - 3466
(2007/10/02)
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