- Visible-Light-Mediated Late-Stage Sulfonylation of Anilines with Sulfonamides
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A visible-light-mediated late-stage sulfonylation of anilines with sulfonamides under simple reaction conditions is presented. Various primary or secondary sulfonamides including several pharmaceuticals were incorporated successfully via N–S bond activati
- Chu, Man-Hei,Du, Xian,Li, Yi-Hui,Luo, Yong,Xu, Xiao-Hong,Yuan, Han,Zhen, Jing-Song
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supporting information
p. 853 - 858
(2022/02/05)
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- Borane-Trimethylamine Complex as a Reducing Agent for Selective Methylation and Formylation of Amines with CO2
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We report herein that a borane-trimethylamine complex worked as an efficient reducing agent for the selective methylation and formylation of amines with 1 atm CO2 under metal-free conditions. 6-Amino-2-picoline serves as a highly efficient catalyst for the methylation of various secondary amines, whereas in its absence, the formylation of primary and secondary amines was achieved in high yield with high chemoselectivity. Mechanistic studies suggest that the 6-amino-2-picoline-borane catalytic system operates like an intramolecular frustrated Lewis pair to activate CO2.
- Zhang, Yanmeng,Zhang, He,Gao, Ke
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p. 8282 - 8286
(2021/10/25)
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- Mechanistic Insight into Copper-Mediated Trifluoromethylation of Aryl Halides: The Role of CuI
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The synthesis, characterization, and reactivity of key intermediates [Cu(CF3)(X)]-Q+ (X = CF3 or I, Q = PPh4) in copper-mediated trifluoromethylation of aryl halides were studied. Qualitative and quantitative studies showed [Cu(CF3)2]-Q+ and [Cu(CF3)(I)]-Q+ were not highly reactive. Instead, a much more reactive species, ligandless [CuCF3] or DMF-ligated species [(DMF)CuCF3], was generated in the presence of excess CuI. On the basis of these results, a general mechanistic map for CuI-promoted trifluoromethylation of aryl halides was proposed. Furthermore, on the basis of this mechanistic understanding, a HOAc-promoted protocol for trifluoromethylation of aryl halides with [Ph4P]+[Cu(CF3)2]- was developed.
- Jin, Yuxuan,Leng, Xuebing,Liu, He,Shen, Qilong,Wu, Jian
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supporting information
p. 14367 - 14378
(2021/09/13)
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- Trialkylammonium salt degradation: Implications for methylation and cross-coupling
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Trialkylammonium (most notably N,N,N-trimethylanilinium) salts are known to display dual reactivity through both the aryl group and the N-methyl groups. These salts have thus been widely applied in cross-coupling, aryl etherification, fluorine radiolabelling, phase-transfer catalysis, supramolecular recognition, polymer design, and (more recently) methylation. However, their application as electrophilic methylating reagents remains somewhat underexplored, and an understanding of their arylation versus methylation reactivities is lacking. This study presents a mechanistic degradation analysis of N,N,N-trimethylanilinium salts and highlights the implications for synthetic applications of this important class of salts. Kinetic degradation studies, in both solid and solution phases, have delivered insights into the physical and chemical parameters affecting anilinium salt stability. 1H NMR kinetic analysis of salt degradation has evidenced thermal degradation to methyl iodide and the parent aniline, consistent with a closed-shell SN2-centred degradative pathway, and methyl iodide being the key reactive species in applied methylation procedures. Furthermore, the effect of halide and non-nucleophilic counterions on salt degradation has been investigated, along with deuterium isotope and solvent effects. New mechanistic insights have enabled the investigation of the use of trimethylanilinium salts in O-methylation and in improved cross-coupling strategies. Finally, detailed computational studies have helped highlight limitations in the current state-of-the-art of solvation modelling of reaction in which the bulk medium undergoes experimentally observable changes over the reaction timecourse. This journal is
- Assante, Michele,Baillie, Sharon E.,Juba, Vanessa,Leach, Andrew G.,McKinney, David,Reid, Marc,Washington, Jack B.,Yan, Chunhui
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p. 6949 - 6963
(2021/06/02)
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- Aminomethylation of Aryl Bromides by Nickel-Catalyzed Electrochemical Redox Neutral Cross Coupling
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We develop an electrochemical nickel-catalyzed aminomethylation of aryl bromides under mild conditions. The convergent paired electrolysis makes full use of anode and cathode processes, free of a terminal oxidant, a sacrificial anode, a metal reductant, and a prefunctionalized radical precursor. In addition, this method exhibits wide functional group tolerance (63 examples), including some sensitive substituents and aromatic heterocycles. This redox neutral cross coupling provides a more environmentally friendly and synthetic practical protocol for forging C(sp2)–C(sp3) bonds.
- Ma, Yueyue,Hong, Jufei,Yao, Xiantong,Liu, Chengyu,Zhang, Ling,Fu, Youtian,Sun, Maolin,Cheng, Ruihua,Li, Zhong,Ye, Jinxing
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supporting information
p. 9387 - 9392
(2021/12/17)
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- Nickel-Catalyzed Amination of Aryl Chlorides with Amides
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A nickel-catalyzed amination of aryl chlorides with diverse amides via C-N bond cleavage has been realized under mild conditions. A broad substrate scope with excellent functional group tolerance at a low catalyst loading makes the protocol powerful for synthesizing various aromatic amines. The aryl chlorides could selectively couple to the amino fragments rather than the carbonyl moieties of amides. Our protocol complements the conventional amination of aryl chlorides and expands the usage of inactive amides.
- Li, Jinpeng,Huang, Changyu,Wen, Daheng,Zheng, Qingshu,Tu, Bo,Tu, Tao
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supporting information
p. 687 - 691
(2021/01/09)
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- Coupling of Alternating Current to Transition-Metal Catalysis: Examples of Nickel-Catalyzed Cross-Coupling
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The coupling of transition-metal to photoredox catalytic cycles through single-electron transfer steps has become a powerful tool in the development of catalytic processes. In this work, we demonstrated that transition-metal catalysis can be coupled to al
- Bortnikov, Evgeniy O.,Semenov, Sergey N.
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supporting information
p. 782 - 793
(2020/12/01)
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- Photon-initiated heterogeneous redox couples for methylation of anilines under mild conditions
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Methylation of anilines has drawn a lot of attention due to their valuable applications and directly using methanol as a methylation reagent is of great advantage. Photon-initiated heterogeneous catalysis of this methylation process meets the requirements of green chemistry. Herein we show that balanced redox zones within carbon nitride supported Pd nanoparticles boost the selectivity of methylation of anilines under mild conditions.
- Zhang, Bing,Gao, Hua,Wang, Wei
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p. 4433 - 4437
(2020/08/10)
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- Zinc Powder Catalysed Formylation and Urealation of Amines Using CO2 as a C1 Building Block?
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Transformation of CO2 into valuable organic compounds catalysed by cheap and biocompatible metal catalysts is one of important topics of current organic synthesis and catalysis. Herein, we report the zinc powder catalysed formylation and urealation of amines with CO2 and (EtO)3SiH under solvent free condition. Using 2 molpercent zinc powder as the catalyst, a series of secondary amines, both the aromatic ones and the aliphatic ones, can be formylated into formamides. When primary aromatic amines were used as the substrates, the reactions produce urea derivatives. The electronic and steric effects from the substrates on the formylation and urealation reactions were observed and discussed. The recovery and reusability of zinc powder were investigated, showing the zinc powder can be reused in the formylation reaction without loss of catalytic activity. The analysis on the reactants/products mixture after filtering out the zinc powder showed the zinc concentration in the mixture is low to 1 ppm. The pathways for the formylation and urealation of amines with this catalytic system were also investigated, and related to the different substrates.
- Du, Chongyang,Chen, Yaofeng
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supporting information
p. 1057 - 1064
(2020/06/30)
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- Selective formylation or methylation of amines using carbon dioxide catalysed by a rhodium perimidine-based NHC complex
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Carbon dioxide can play a vital role as a sustainable feedstock for chemical synthesis. To be viable, the employed protocol should be as mild as possible. Herein we report a methodology to incorporate CO2 into primary, secondary, aromatic or alkyl amines catalysed by a Rh(i) complex bearing a perimidine-based NHC/phosphine pincer ligand. The periminide-based ligand belongs to a class of 6-membered NHC ligand accessed through chelate-assisted double C-H activation. N-Formylation and -methylation of amines were performed using a balloon of CO2, and phenylsilane as the reducing agent. Product selectivity between formylated and methylated products was tuned by changing the solvent, reaction temperature and the quantity of phenylsilane used. Medium to excellent conversions, as well as tolerance to a range of functional groups, were achieved. Stoichiometric reactions with reactants employed in catalysis and time course studies suggested that formylation and methylation reactions of interest begin with hydrosilylation of CO2 followed by reaction with amine substrates.
- Lam, Raphael H.,McQueen, Caitlin M. A.,Pernik, Indrek,McBurney, Roy T.,Hill, Anthony F.,Messerle, Barbara A.
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supporting information
p. 538 - 549
(2019/02/14)
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- B(C6F5)3-Catalyzed C-H Alkylation of N-Alkylamines Using Silicon Enolates without External Oxidant
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An efficient method for the coupling of N-alkylamines with silicon enolates to generate β-amino carbonyl compounds is disclosed. These reactions proceed by activation of α-amino C-H bonds by B(C6F5)3, which likely generate
- Chan, Jessica Z.,Chang, Yejin,Wasa, Masayuki
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supporting information
p. 984 - 988
(2019/02/14)
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- Amination of Aromatic Halides and Exploration of the Reactivity Sequence of Aromatic Halides
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A base-promoted amination of aromatic halides has been developed using a limited amount of dimethylformamide (DMF) or amine as an amino source. Various aryl halides, including F, Cl, Br, and I, have been successfully aminated in good to excellent yields. Although the amination of aromatic halides with amines or DMF is usually considered as an aromatic nucleophilic substitution (SNAr) process, and the reactivity of an aromatic halide is F > Cl > Br > I, the reactivity of aromatic halides in this system was found to be I > Br a‰ F > Cl. This protocol also showed a good regioselectivity for multihalogenated aromatics. This protocol is valuable for industrial application due to the simplicity of operation, the unrestricted availability of amino sources and aromatic halides, transition metal-free conditions, no requirement for solvent, and scalability.
- Yang, Chu,Zhang, Feng,Deng, Guo-Jun,Gong, Hang
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p. 181 - 190
(2019/01/10)
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- Three-Component Aminoselenation of Arynes
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The three-component coupling of tertiary amines, arynes, and aryl selenium bromide or diaryl diselenide as an electrophilic selenium source allowing the synthesis of 2-selanyl aniline derivatives is reported. This aminoselenation reaction of arynes installs a C-N and C-Se bond under mild conditions, and the products are formed in moderate to good yields. This reaction is compatible with various functional groups, and the preliminary studies on the mechanism of the reaction is also provided.
- Gaykar, Rahul N.,Guin, Avishek,Bhattacharjee, Subrata,Biju, Akkattu T.
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supporting information
p. 9613 - 9617
(2019/11/28)
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- 1,4-Dioxane-Tuned Catalyst-Free Methylation of Amines by CO2 and NaBH4
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A catalyst-free reductive functionalization of CO2 with amines and NaBH4 was developed. The N-methylation of amines was carried out with CO2 as a C1 building block and 1,4-dioxane as the solvent. Notably, the six-electron reduction of CO2 to form the methyl group occurred simultaneously with formation of the C?N bond to give the N-methylated amine.
- Guo, Zhiqiang,Zhang, Bo,Wei, Xuehong,Xi, Chanjuan
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p. 2296 - 2299
(2018/07/31)
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- Transformation of N, N-Dimethylaniline N-Oxides into Diverse Tetrahydroquinoline Scaffolds via Formal Povarov Reactions
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A one-pot protocol for the assembly of diversely functionalized tetrahydro-, hexahydrofuro-, hexahydropyrano-, and tetrahydrobenzofuroquinolines from N,N-dimethylaniline N-oxides and various electron-rich olefins in a tandem Polonovski-Povarov sequence is reported. Following activation of the N-O bond with Boc2O, an exocyclic iminium ion is unveiled upon exposure to tin(IV) chloride. A formal inverse-electron-demand aza-Diels-Alder cyclization generates the tetrahydroquinoline core of 29 examples in up to 92% yield.
- Bush, Timothy S.,Yap, Glenn P. A.,Chain, William J.
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supporting information
p. 5406 - 5409
(2018/09/13)
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- Base-oxidant promoted metal-free N-demethylation of arylamines
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A metal-free oxidative N-demethylation of arylamines with triethylamine as a base and tert-butyl hydroperoxide (TBHP) as oxidant is reported in this paper. The reaction is general, practical, inexpensive, non-toxic, and the method followed is environmentally benign, with moderate to good yields. [Figure not available: see fulltext.]
- Botla, Vinayak,Barreddi, Chiranjeevi,Daggupati, Ramana V,Malapaka, Chandrasekharam
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p. 1469 - 1473
(2016/09/19)
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- Room-temperature copper-catalyzed arylation of dimethylamine and methylamine in neat water
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The first room-temperature copper-catalyzed arylations of dimethylamine and methylamine in neat water have been developed. Using a combination of CuI and 6,7-dihydroquinolin-8(5 H)-one oxime as catalyst, dimethylamine is arylated with various aryl halides to give the corresponding products in good to excellent yields. Further, this catalysis enables the selective arylation of methylamine to afford the high yields of monoarylated methylamines as the sole products.
- Wang, Deping,Kuang, Daizhi,Zhang, Fuxing,Yang, Chunlin,Zhu, Xiaoming
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supporting information
p. 714 - 718
(2015/03/18)
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- The 2,4-dimethyl-7-pentafluorosulfanyl-5-(trifluoromethyl)dibenzo[b,d] thiophenium trifluoromethanesulfonate: The SF5-analog of Umemoto salt
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The SF5-analog of the Umemoto salt was synthesized in just two steps by combining our recently reported SF5-biaryl synthesis, via Suzuki coupling with 4-(pentafluorosulfanyl)benzenediazonium tetrafluoroborate, with Magnier's one-pot synthesis of dibenzothiophenium salts employing CF 3SO2Na and triflic anhydride. The trifluoromethylating power of this novel onium salt toward reactive arenes was tested in a survey study on small scale.
- Okazaki, Takao,Laali, Kenneth K.,Reddy, A. Srinivas
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- Metal-free catalyst for the chemoselective methylation of amines using carbon dioxide as a carbon source
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N-methylation of amines is an important step in the synthesis of many pharmaceuticals and has been widely applied in the preparation of other key intermediates and chemicals. Therefore, the development of efficient methylation methods has attracted considerable attention. In this respect, carbon dioxide is an attractive C1 building block because it is an abundant, renewable, and nontoxic carbon source. Consequently, we developed a highly chemoselective, metal-free catalytic system that operates under ambient conditions for the N-methylation of amines. The methylation of amines with CO2 as C1 source and Ph2SiH2 as reducing agent was achieved with an N-heterocyclic carbene (NHC) as the catalyst. The catalyst is tolerant toward a variety of functional groups (including esters and ethers, nitro, nitrile, and carbonyl groups, and unsaturated C-C bonds); the reaction uses commercially available reagents and can be performed on a gram scale.
- Das, Shoubhik,Bobbink, Felix D.,Laurenczy, Gabor,Dyson, Paul J.
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supporting information
p. 12876 - 12879
(2016/02/18)
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- Methylation of secondary amines with dialkyl carbonates and hydrosilanes catalysed by iron complexes
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Methylation of secondary amines was achieved using dimethyl carbonate or diethyl carbonate as the C1 source under the catalysis of well-defined half-sandwich iron complexes bearing an N-heterocyclic carbene ligand. The reaction proceeded under mild conditions in the presence of hydrosilanes as the reductants, and the amines were obtained with good to excellent isolated yields. This journal is
- Zheng, Jianxia,Darcel, Christophe,Sortais, Jean-Baptiste
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supporting information
p. 14229 - 14232
(2014/12/11)
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- One-pot sandmeyer trifluoromethylation and trifluoromethylthiolation
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Practical one-pot procedures were developed for both Sandmeyer-type trifluoromethylations and trifluoromethylthiolations. Starting from broadly available (hetero)aromatic amines, various benzotrifluorides were synthesized in high yields via in situ diazotization and copper-mediated trifluoromethylation using the inexpensive Ruppert-Prakash trifluoromethylating reagent. In the presence of sodium thiocyanate as a sulfur source, aryl trifluoromethyl thioethers are exclusively formed.
- Bayarmagnai, Bilguun,Matheis, Christian,Risto, Eugen,Goossen, Lukas J.
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supporting information
p. 2343 - 2348
(2014/07/21)
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- A general method for N-methylation of amines and nitro compounds with dimethylsulfoxide
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DMSO methylates a broad range of amines in the presence of formic acid, providing a novel, green and practical method for amine methylation. The protocol also allows the one-pot transformation of aromatic nitro compounds into dimethylated amines in the presence of a simple iron catalyst. Not just a solvent: DMSO methylates a broad range of amines in the presence of formic acid, providing a novel, green and practical method for amine methylation. The protocol also allows the one-pot transformation of aromatic nitro compounds into dimethylated amines in the presence of a simple iron catalyst. Copyright
- Jiang, Xue,Wang, Chao,Wei, Yawen,Xue, Dong,Liu, Zhaotie,Xiao, Jianliang
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supporting information
p. 58 - 63
(2014/01/17)
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- Silver-catalysed trifluoromethylation of arenes at room temperature
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A variety of heteroarenes and electron rich arenes can be trifluoromethylated at room temperature with TMSCF3, catalytic silver and PhI(OAc)2.
- Seo, Sangwon,Taylor, John B.,Greaney, Michael F.
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supporting information
p. 6385 - 6387
(2013/08/23)
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- Sandmeyer trifluoromethylation of arenediazonium tetrafluoroborates
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Copper capabilities: Diazonium salts are converted into the corresponding trifluoromethyl derivatives in the presence of a trifluoromethyl-copper complex generated in situ from CuSCN and the inexpensive, easy-to-use trifluoromethylating reagent Me3Si-CF3 (see scheme). This Sandmeyer-type reaction allows the straightforward synthesis of trifluoromethylated arenes and heteroarenes from the corresponding amines. Copyright
- Danoun, Grégory,Bayarmagnai, Bilguun,Grünberg, Matthias F.,Goo?en, Lukas J.
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p. 7972 - 7975
(2013/08/23)
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- Mechanistic investigation of oxidative Mannich reaction with tert-butyl hydroperoxide. the role of transition metal salt
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A general mechanism is proposed for transition metal-catalyzed oxidative Mannich reactions of N,N-dialkylanilines with tert-butyl hydroperoxide (TBHP) as the oxidant. The mechanism consists of a rate-determining single electron transfer (SET) that is uniform from 4-methoxy- to 4-cyano-N,N-dimethylanilines. The tert-butylperoxy radical is the major oxidant in the rate-determining SET step that is followed by competing backward SET and irreversible heterolytic cleavage of the carbon-hydrogen bond at the α-position to nitrogen. A second SET completes the conversion of N,N-dimethylaniline to an iminium ion that is subsequently trapped by the nucleophilic solvent or the oxidant prior to formation of the Mannich adduct. The general role of Rh2(cap) 4, RuCl2(PPh3)3, CuBr, FeCl 3, and Co(OAc)2 in N,N-dialkylaniline oxidations by T-HYDRO is to initiate the conversion of TBHP to tert-butylperoxy radicals. A second pathway, involving O2 as the oxidant, exists for copper, iron, and cobalt salts. Results from linear free-energy relationship (LFER) analyses, kinetic and product isotope effects (KIE and PIE), and radical trap experiments of N,N-dimethylaniline oxidation by T-HYDRO in the presence of transition metal catalysts are discussed. Kinetic studies of the oxidative Mannich reaction in methanol and toluene are also reported.
- Ratnikov, Maxim O.,Doyle, Michael P.
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supporting information
p. 1549 - 1557
(2013/03/14)
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- Reductive amination of tertiary anilines and aldehydes
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An unprecedented oxidant-mediated reductive amination of tertiary anilines and aldehydes without external reducing agents was developed via the nucleophilic attack of the oxygen atom of the carbonyl group to in situ generated iminium ions, in which tertiary anilines were used as both nitrogen source and reducing agent for the first time. The Royal Society of Chemistry 2013.
- Lv, Yunhe,Zheng, Yiying,Li, Yan,Xiong, Tao,Zhang, Jingping,Liu, Qun,Zhang, Qian
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supporting information
p. 8866 - 8868
(2013/09/24)
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- Palladium/copper-catalyzed oxidative C-H alkenylation/N-dealkylative carbonylation of tertiary anilines
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C-H/C-N activation: The first palladium/copper-catalyzed aerobic oxidative C-H alkenylation/N-dealkylative carbonylation of tertiary anilines has been developed. Various functional groups were tolerated and acrylic ester could also be suitable substrates. This transformation provided efficient and straightforward synthesis of biologically active 3-methyleneindolin-2-one derivatives from cheap and simple substrates. Copyright
- Shi, Renyi,Lu, Lijun,Zhang, Hua,Chen, Borui,Sha, Yuchen,Liu, Chao,Lei, Aiwen
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supporting information
p. 10582 - 10585
(2013/10/21)
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- Copper-catalyzed trifluoromethylation of aryl- and vinylboronic acids with generation of CF3-radicals
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The selective trifluoromethylation of aryl- and vinylboronic acids proceeds smoothly with CF3SO2Na (Langlois reagent) in the presence of copper catalysts and t-BuOOH. Therefore, the method relies both on transition metal catalysis an
- Li, Yang,Wu, Lipeng,Neumann, Helfried,Beller, Matthias
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supporting information
p. 2628 - 2630
(2013/04/23)
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- FLUOROALKYLATION METHODS AND REAGENTS
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A method of forming a fluorinated molecular entity includes reacting in a reaction mixture an aromatic halide, copper, a fluoroalkyl group, and a ligand. The aromatic halide includes an aromatic group and a halogen substituent bonded to the aromatic group. The ligand includes at least one group-V donor selected from phosphorus and an amine. The overall molar ratio of copper to aromatic halide in the reaction mixture is from 0.2 to 3. The method further includes forming a fluoroalkylarene including the aromatic group and the fluoroalkyl group bonded to the aromatic group. A composition, which may be used in the method, consists essentially of copper, the fluoroalkyl group, and the ligand, where the molar ratio of copper to the fluoroalkyl group is approximately 1.
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-
Page/Page column title page; 6; 28
(2012/03/11)
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- A broadly applicable copper reagent for trifluoromethylations and perfluoroalkylations of aryl iodides and bromides
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(Chemical Presented) Well compatible: The trifluoromethylations and perfluoroalkylations of aryl iodides and some aryl bromides with trifluoromethyl and perfluoroalkylcopper(I) phenanthroline complexes occur with broad scope at 25-50 8C (see scheme). The trifluoromethyl complex is prepared from inexpensive reagents and can be used in situ or isolated. The reactions tolerate a range of substituents and also occur with heteroaromatic systems.
- Morimoto, Hiroyuki,Tsubogo, Tetsu,Litvinas, Nichole D.,Hartwig, John F.
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supporting information; experimental part
p. 3793 - 3798
(2011/05/15)
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- Iron-catalyzed regioselective direct oxidative aryl-aryl cross-coupling
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Regioselective iron-catalyzed cross-dehydrogenative coupling (CDC) of two aromatic compounds using tert-BuOOH as oxidant under mild conditions has been reported. The direct oxidative coupling reaction is selective toward creation of a carbon-carbon bond at the position ortho to the functional groups of the substrates, completely preventing the homocoupled products. The C-C bond-forming reaction makes the method versatile, leading to functionalized 2,2′-disubstituted biaryls (Figure presented).
- Chandrasekharam, Malapaka,Chiranjeevi, Barreddi,Gupta, Kankatala S.V.,Sridhar
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experimental part
p. 10229 - 10235
(2012/01/15)
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- Copper-catalyzed trifluoromethylation of aryl iodides with potassium (trifluoromethyl)trimethoxyborate
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Potassium (trifluoromethyl)trimethoxyborate is introduced as a new source of CF3 nucleophiles in copper-catalyzed trifluoromethylation reactions. The crystalline salt is stable on storage, easy to handle, and can be obtained in near-quantitative yields simply by mixing B(OMe)3, CF3SiMe3, and KF. The trifluoromethylation reagent allows the conversion of various aryl iodides into the corresponding benzotrifluorides in high yields under mild, base-free conditions in the presence of catalytic quantities of a CuI/1,10-phenanthroline complex.
- Knauber, Thomas,Arikan, Fatih,Roeschenthaler, Gerd-Volker,Goossen, Lukas J.
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experimental part
p. 2689 - 2697
(2011/04/15)
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- N-Demethylation of N,N-Dimethylanilines by the benzotriazole N-Oxyl radical: Evidence for a two-step electron transfer-proton transfer mechanism
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"Chemical Equation Presented" The reaction of the benzotriazole N-oxyl radical (BTNO) with a series of 4-X-N,N-dimethylanilines (X = CN, CF 3, CO2CH2CH3, CH3, OC6H5, OCH3) has been investigated in CH 3CN. Product analysis shows that the radical, 4-X-C6H 4N(CH3)CH2·, is first formed, which can lead to the N-demethylated product or the product of coupling with BTNO. Reaction rates were found to increase significantly by increasing the electron-donating power of the aryl substituents (p+ = -3.8). With electron-donating substituents (X = CH3, OC6H5, OCH3), no intermolecular deuterium kinetic isotope effect (DKIE) and a substantial intramolecular DKIE are observed. With electron-withdrawing substituents (X = CN, CF3, CO2CH2CH 3), substantial values of both intermolecular and intramolecular DKIEs are observed. These results can be interpreted on the basis of an electron-transfer mechanism from the N,N-dimethylanilines to the BTNO radical followed by deprotonation of the anilinium radical cation (ET-PT mechanism). By applying the Marcus equation to the kinetic data for X = CH3, OC 6H5, OCH3 (rate-determining ET), a reorganization energy for the ET reaction was determined (λ BTNO/DMA= 32.1 kcal mol- 1). From the self-exchange reorganization energy for the BTNO/BTNO- couple, a self-exchange reorganization energy value of 31.9 kcal mol-1 was calculated for the DMA·+/DMA couple.
- Baciocchi, Enrico,Bietti, Massimo,Lanzalunga, Osvaldo,Lapi, Andrea,Raponi, Daniele
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supporting information; experimental part
p. 1378 - 1385
(2010/06/11)
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- Iron-catalyzed synthesis of glycine derivatives via carbon-nitrogen bond cleavage using diazoacetate
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Treatment of tertiary amines with diazoacetate in the presence of a catalytic amount of an iron salt, FeCl3, in ethanol gave glycine derivatives. In this reaction, a carbon-nitrogen single bond of the amine was cleaved. The Royal Society of Chemistry 2010.
- Kuninobu, Yoichiro,Nishi, Mitsumi,Takai, Kazuhiko
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supporting information; experimental part
p. 8860 - 8862
(2011/02/28)
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- A new method for the synthesis of trifluoromethylating agents-Diaryltrifluoromethylsulfonium salts
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A new synthetic method has been developed to prepare diaryltrifluoromethylsulfonium salts from diaryldifluorosulfuranes by the action of Me3SiCF3/F-. This reaction is the transformation of nucleophilic trifluoro-methylating reagent into electrophilic one.
- Yagupolskii, Lev M.,Matsnev, Andrej V.,Orlova, Raisa K.,Deryabkin, Boris G.,Yagupolskii, Yurii L.
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p. 131 - 136
(2008/09/21)
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- Synthesis of N,N-dimethylamines via Barbier-Grignard-type electrophilic amination
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Aryl Grignard reagents react with N,N-dimethyl O-(mesitylenesulfonyl)- hydroxylamine in THF under Barbier conditions at room temperature and give N,Ndimethylanilines with high yields in a 2-h reaction. The amination yield of in situ Grignard reagents were not lower than those of preformed aryl Grignard reagents. In situ cycloalkyl-, allyl-, and benzylmagnesium bromides did not react with N,Ndimethyl O-(mesitylenesulfonyl)hydroxylamine, except that amination of in situ n-hexylmagnesium bromide resulted in a medium yield. Grignard-Barbier-type amination of aryl bromides with N,N-dimethyl O-(mesitylenesulfonyl)hydroxylamine provides a new alternative route for the synthesis of N,N-dimethylanilines. Copyright Taylor & Francis Group, LLC.
- Erdik, Ender,Ates, Selma
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p. 2813 - 2818
(2007/10/03)
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- Dynamics of α-CH deprotonation and α-desilylation reactions of tertiary amine cation radicals
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Time-resolved laser spectroscopy has been used to generate and characterize a series of tertiary amine cation radicals and to determine the rates of their α-CH deprotonation and α-desilylation reactions with bases and silophiles. Laser excitation (308 nm) of a 60:40 MeOH:MeCN solution of PhNMe2 (DMA) and 1,4-dicyanobenzene (DCB) promotes SET-induced formation of the DMA cation radical (460 nm) and DCB anion radical (340 nm), which undergo decay by back electron transfer at nearly equal rates and with respective second-order rate constants of 1.1 × 1010 and 1.3 × 1010 M-1 s-1 (25°C). The decay rate is lowered (ca. 4-fold) by the inclusion of salts (ca. 0.1 M) such as nBu4NClO4, LiClO4, HBu4NCl, nBu4NBF4, and nBu4NO3SCF3 in MeOH-MeCN and by changing the solvent from MeCN to MeOH and to EtOH. The cation radical of PhNMeCH2(TMS) (480 nm) and the simultaneously generated DCB anion radical undergo second order decay in MeCN with respective rate constants of 1.2 × 1010 and 9.9 × 109 M-1 s-1 (25°C). The silylamine cation radical decay rate was found to be governed by the concentration of silophiles (MeOH, H2O and nBu4NF) in MeCN solutions. The observations are consistent with a silophile-induced desilylation process with second-order rate constants of 8.9 × 105 (MeOH), 1.27 × 106 (H2O), and 3.1 × 109 M-1 s-1 (nBu4NF). The rate of DMA cation radical decay is a function of base concentration. Both nBu4NOAc and nBu4NO2CCF3 react with the DMA cation radical (in 60:40 MeOH:MeCN containing 0.1 M nBu4NClO4) with second-order rate constants for α-CH deprotonation of 3.1 × 105 and 8 × 104 M-1 s-1 (25°C), respectively. Measurements with PhN(CD3)2 and nBu4NOAc gave a kH/kD for α-CH deprotonation of 3.6 (60:40 MeOH:MeCN, 25°C). Para-substituents have a pronounced effect on the rate of α-CH deprotonation by nBu4NOAc; second-order rate constants of 2.3 × 104, 1.1 × 105, and 2.5 × 106 M-1 s-1 were determined for the P-OMeC6H4NMe2, p-MeC6H4NMe2 and p-CF3C6H4NMe2 cation radicals. Studies with Ph2NMe demonstrated that its cation radical (645 nm) can be generated by SET to DCB and that its decay through α-CH deprotonation by nBu4NOAc has a second-order rate constant of 9.5 × 105 M-1 s-1 and a kH/kD value of 2.8 (25:75 MeOH:MeCN, 25°C). Finally, the effects of α-substituents on the rates of nBu4-NOAc-induced α-CH deprotonation of tertiary amine cation radicals were evaluated by use of the amines Ph2NCHR1R2. The second-order rate constants (25°C, 25:75 MeOH:MeCN) are 2.3 × 105 (R1 = Me, R2 = H), 1.7 × 105 (R1 = R2 = Me), 3.2 × 106 (R1 = Ph, R2 = H), 2.6 × 106 (R1 = CH=CH2, R2 = H), and 7.0 × 107 M-1 s-1 (R1 = C≡CH, R2 = H).
- Zhang, Xiaoming,Yeh, Syun-Ru,Hong, Seok,Freccero, Mauro,Albini, Angelo,Falvey, Daniel E.,Mariano, Patrick S.
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p. 4211 - 4220
(2007/10/02)
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- TRIFLUOROMETHYLATION OF AROMATIC AMINO AND THIO COMPOUNDS BY BISTRIFLUOROMETHYL TELLURIDE
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The reaction of aromatic and heterocyclic amines with (CF3)2Te gave the products from trifluoromethylation in the aromatic ring.The reaction with the corresponding thiols gave S-trifluoromethyl derivatives.
- Naumann, D.,Pazenok, S. V.,Turra, V.
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p. 128 - 130
(2007/10/02)
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- Interionic Structure of N-Ethyl-N,N-dimethylanilinium Benzenesulfonate Ion Pairs from Electric Dipole Moments
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Electric dipole moments are measured for N-ethyl-N,N-dimethylanilinium benzenesulfonate ion pairs with polar substituents in either phenyl ring.The solvent is octanoic acid (εO = 2.46).The interionic geometry is deduced by dipole vector analysi
- Comeford, Lorrie,Grunwald, Ernest,Begum, M. Kohinoor,Pradhan, Jyotsna
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p. 2714 - 2716
(2007/10/02)
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- Photochemical Trifluoromethylation of Some Aromatic and Heteroaromatic Compounds with Trifluoromethyl Bromide
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The photochemical introduction of trifluoromethyl group with CF3Br in aromatic and heteroaromatic rings was investigated for 9 compounds.Naphthalene, anthracene, anisole, N,N-dimethylaniline, ferrocene, benzothiophene, isoquinoline, and N-methylpyrrole gave trifluoromethylated products in 6.5-100percent yields.In one step from uracil, a pharmacologically important 5-trifluoromethyluracil can be synthesized by this method in 11percent yield.Based on the mechanistic study carried out for the naphthalene-CF3Br-CH3CN system, the reaction is found to proceed via the electron transfer from an excited singlet state of naphthalene to CF3Br.
- Akiyama, Takeo,Kato, Kohji,Kajitani, Masatsugu,Sakaguchi, Yoshio,Nakamura, Junko,et al.
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p. 3531 - 3538
(2007/10/02)
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