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Three-Component Coupling Involving Arynes, Aromatic Tertiary Amines, and Aldehydes via Aryl-Aryl Amino Group Migration
The transition-metal-free multicomponent coupling of arynes, aromatic tertiary amines, and aldehydes proceeding via the aryl to aryl amino group migration has been demonstrated. This protocol allows rapid access to ortho-functionalized tertiary amines in moderate to good yields. Moreover, activated ketones can also be used as the aldehyde component in the present reaction. The similarity of the aryl-aryl tertiary amino group migration with the Smiles rearrangement is striking.
Bhojgude, Sachin Suresh,Baviskar, Dnyaneshwar R.,Gonnade, Rajesh G.,Biju, Akkattu T.
p. 6270 - 6273
(2015)
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Highly Chemoselective Deoxygenation of N-Heterocyclic N-Oxides Using Hantzsch Esters as Mild Reducing Agents
Herein, we disclose a highly chemoselective room-temperature deoxygenation method applicable to various functionalized N-heterocyclic N-oxides via visible light-mediated metallaphotoredox catalysis using Hantzsch esters as the sole stoichiometric reductant. Despite the feasibility of catalyst-free conditions, most of these deoxygenations can be completed within a few minutes using only a tiny amount of a catalyst. This technology also allows for multigram-scale reactions even with an extremely low catalyst loading of 0.01 mol %. The scope of this scalable and operationally convenient protocol encompasses a wide range of functional groups, such as amides, carbamates, esters, ketones, nitrile groups, nitro groups, and halogens, which provide access to the corresponding deoxygenated N-heterocycles in good to excellent yields (an average of an 86.8% yield for a total of 45 examples).
An, Ju Hyeon,Kim, Kyu Dong,Lee, Jun Hee
supporting information
p. 2876 - 2894
(2021/02/01)

Borane-Trimethylamine Complex as a Reducing Agent for Selective Methylation and Formylation of Amines with CO2
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
supporting information
p. 8282 - 8286
(2021/10/25)

CO2-tuned highly selective reduction of formamides to the corresponding methylamines
We herein describe an efficient, CO2-tuned and highly selective C-O bond cleavage of N-methylated formanilides. With easy-to-handle and commercially available NaBH4 as the reductant, a variety of formanilides could be turned into the desired tertiary amines in moderate to excellent yields. The role of CO2 has been investigated in detail, and the mechanism is proposed on the basis of experiments.
Chao, Jianbin,Guo, Zhiqiang,Pang, Tengfei,Wei, Xuehong,Xi, Chanjuan,Yan, Leilei
supporting information
p. 7534 - 7538
(2021/10/12)

Univariate classification of phosphine ligation state and reactivity in cross-coupling catalysis
Chemists often use statistical analysis of reaction data with molecular descriptors to identify structure-reactivity relationships, which can enable prediction and mechanistic understanding. In this study, we developed a broadly applicable and quantitative classification workflow that identifies reactivity cliffs in 11 Ni- and Pd-catalyzed cross-coupling datasets using monodentate phosphine ligands. A distinctive ligand steric descriptor, minimum percent buried volume [%Vbur (min)], is found to divide these datasets into active and inactive regions at a similar threshold value. Organometallic studies demonstrate that this threshold corresponds to the binary outcome of bisligated versus monoligated metal and that %Vbur (min) is a physically meaningful and predictive representation of ligand structure in catalysis.
Newman-Stonebraker, Samuel H.,Smith, Sleight R.,Borowski,Peters, Ellyn,Gensch, Tobias,Johnson, Heather C.,Sigman, Matthew S.,Doyle, Abigail G.
p. 301 - 308
(2021/10/22)

Double Ligands Enabled Ruthenium Catalyzed ortho-C?H Arylation of Dialkyl Biarylphosphines: Straight and Economic Synthesis of Highly Steric and Electron-Rich Aryl-Substituted Buchwald-Type Phosphines
A double-ligands enabled ruthenium catalyzed C(sp2)?H arylation of dialkyl phosphines is described, which provides a straight access to aryl-substituted dialkyl phosphine ligands. The combination of 1,3-diketone and amino acid ligands is essential for this transformation. An important six-membered cycloruthenium intermediate was successfully isolated and characterized by X-ray diffraction. Mechanistic studies showed that the 1,3-diketone promoted the process of oxidative addition of cycloruthenium intermediate. Some of modified CyJohnPhos ligands exhibited highly catalytic activity in palladium catalyzed C?N bond formation. (Figure presented.).
Wang, Liang-Neng,Tang, Pan-Ting,Li, Ming,Li, Jia-Wei,Liu, Yue-Jin,Zeng, Ming-Hua
supporting information
p. 2843 - 2849
(2021/05/03)

Synthesis of N-heterocyclic carbene-Pd(II)-5-phenyloxazole complexes and initial studies of their catalytic activity toward the Buchwald-Hartwig amination of aryl chlorides
Three new N-heterocyclic carbene (NHC)-Pd(II) complexes using 5-phenyloxazole as the ancillary ligand have been obtained in moderate to good yields by a one-pot reaction of the corresponding imidazolium salts, palladium chloride and 5-phenyloxazole under mild conditions. Initial studies showed that one of the complexes is an efficient catalyst for the Buchwald-Hartwig amination of aryl chlorides with various secondary and primary amines under the varied catalyst loading of 0.01-0.05 mol%, thus it will enrich the chemistry of NHCs and give an alternative catalyst for the coupling of challenging while cost-low aryl chlorides.
Zhang, Zhi-Mao,Xu, Yu-Ting,Shao, Li-Xiong
(2021/04/19)

Effect of Precatalyst Oxidation State in C-N Cross-Couplings with 2-Phosphinoimidazole-Derived Bimetallic Pd(I) and Pd(II) Complexes
We report the catalytic activity of two phosphinoimidazole-derived bimetallic palladium complexes in Pd-catalyzed amination reactions. Our studies demonstrate that the starting oxidation state (Pd(I) or Pd(II)) of the dimeric complex has a significant effect on the efficiency of the catalytic reaction. The corresponding Pd(I) complex shows higher reactivity in Buchwald-Hartwig aminations, while the Pd(II) complex is much more reactive in carbonylative amination reactions. These new dimeric palladium complexes provide good to excellent reactivity and yields in the amination reactions tested.
Martinez, Erin E.,Moreno, Mariur Rodriguez,Barksdale, Caleb A.,Michaelis, David J.
supporting information
p. 2763 - 2767
(2021/08/27)

Mesoionic N-heterocyclic olefin catalysed reductive functionalization of CO2for consecutiveN-methylation of amines
A mesoionic N-heterocyclic olefin (mNHO) was introduced as a metal-free catalyst for the reductive functionalization of CO2leading to consecutive doubleN-methylation of primary amines in the presence of 9-borabicyclo[3.3.1]nonane (9-BBN). A wide range of secondary amines and primary amines were successfully methylated under mild conditions. The catalyst sustained over six successive cycles ofN-methylation of secondary amines without compromising its activity, which encouraged us to check its efficacy towards doubleN-methylation of primary amines. Moreover, this method was utilized for the synthesis of two commercially available drug molecules. A detailed mechanistic cycle was proposed by performing a series of control reactions along with the successful characterisation of active catalytic intermediates either by single-crystal X-ray study or by NMR spectroscopic studies in association with DFT calculations.
Das, Arpan,Maji, Subir,Mandal, Swadhin K.
p. 12174 - 12180
(2021/09/28)

Mediator-Enabled Electrocatalysis with Ligandless Copper for Anaerobic Chan-Lam Coupling Reactions
Simple copper salts serve as catalysts to effect C-X bond-forming reactions in some of the most utilized transformations in synthesis, including the oxidative coupling of aryl boronic acids and amines. However, these Chan-Lam coupling reactions have historically relied on chemical oxidants that limit their applicability beyond small-scale synthesis. Despite the success of replacing strong chemical oxidants with electrochemistry for a variety of metal-catalyzed processes, electrooxidative reactions with ligandless copper catalysts are plagued by slow electron-transfer kinetics, irreversible copper plating, and competitive substrate oxidation. Herein, we report the implementation of substoichiometric quantities of redox mediators to address limitations to Cu-catalyzed electrosynthesis. Mechanistic studies reveal that mediators serve multiple roles by (i) rapidly oxidizing low-valent Cu intermediates, (ii) stripping Cu metal from the cathode to regenerate the catalyst and reveal the active Pt surface for proton reduction, and (iii) providing anodic overcharge protection to prevent substrate oxidation. This strategy is applied to Chan-Lam coupling of aryl-, heteroaryl-, and alkylamines with arylboronic acids in the absence of chemical oxidants. Couplings under these electrochemical conditions occur with higher yields and shorter reaction times than conventional reactions in air and provide complementary substrate reactivity.
Walker, Benjamin R.,Manabe, Shuhei,Brusoe, Andrew T.,Sevov, Christo S.
supporting information
p. 6257 - 6265
(2021/05/07)

Catalytic Deoxygenation of Amine and Pyridine N-Oxides Using Rhodium PCcarbeneP Pincer Complexes
Rhodium PCcarbeneP pincer complexes 1-L (L = PPh3, PPh2(C6F5), PCy3) readily facilitate deoxygenation of amine and pyridine N-oxides. The resulting complexes exhibit δ2-C= O coordination of the resulting keto POP pincer ligand. These δ2-Ca? O linkages in the metalloepoxide complexes are readily reduced by isopropyl alcohol and various benzylic alcohols. Thus, efficient catalytic deoxygenation of amine and pyridine N-oxides is possible using complexes 1-L and isopropyl alcohol. This represents a pioneering example of PCcarbeneP pincer complexes being used as catalysts for catalytic deoxygenation.
Tinnermann, Hendrik,Sung, Simon,Cala, Beatrice A.,Gill, Hashir J.,Young, Rowan D.
p. 797 - 803
(2020/03/13)

Pyrazolyl bistriazolyl phosphine compound and application of pyrazolyl bistriazolyl phosphine compound
The invention discloses a pyrazolyl bistriazolyl phosphine compound and application thereof. The invention discloses a compound shown as a formula I. In the formula I, R1 is hydrogen, C1-C6 alkyl or phenyl; R2 and R3 are phenyl; R4 and R5 are independently a C1-C6 alkyl group, a C3-C8 cycloalkyl group, or a phenyl group. The pyrazolyl bistriazolyl phosphine compound disclosed by the invention is stable in property, excellent in catalytic effect and high in selectivity, and can be applied to catalytic coupling of amine, boric acid compounds and halides.
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Paragraph 0224-0228; 0263-0266; 0304-0309; 0314-0317

(2020/07/24)

Preparation method of pyrazole bistriazolylphosphine compound
The invention discloses a preparation method of a pyrazole bistriazolylphosphine compound. The invention discloses a preparation method of a compound as shown in a formula I. The preparation method comprises the following step: under the action of an alkali, carrying out a phosphonation reaction process as shown in the specification on a compound as shown in a formula II and a compound as shown ina formula III in a solvent in the presence of protective gas to obtain the compound as shown in the formula I, wherein R1 is hydrogen, a C1-C6 alkyl group or a phenyl group, R2 and R3 are phenyl, R4and R5 are independently a C1-C6 alkyl group, a C3-C8 cycloalkyl group or a phenyl group and x is halogen. The pyrazolyl bistriazolylphosphine compound obtained by the preparation method disclosed bythe invention is stable in property, excellent in catalytic effect and high in selectivity, and can be applied to catalytic coupling of amine, boric acid compounds and halides.
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Paragraph 0222-0226; 0261-0264; 0302-0307; 0312-0315

(2020/05/30)

C–N Cross-coupling Reactions of Amines with Aryl Halides Using Amide-Based Pincer Nickel(II) Catalyst
Abstract: An approach to C–N cross-coupling reactions of aryl halides with amines in the presence of an amide-based pincer nickel(II) catalyst (2) is described. For 3?h reactions at 110?°C with 0.2?mol% catalyst, aryl bromides gave higher turnover numbers (TON) than the corresponding chlorides or iodides. Both primary and secondary amines could be used with the former giving higher TON. However, sterically hindered amines showed lower TON. In elucidating the mechanism of this nickel complex-catalyzed C–N cross coupling reaction it was found that the rate of reaction was unchanged in the presence of radical quenchers and a plausible Ni(I)–Ni(III) pathway is proposed. Graphic Abstract: [Figure not available: see fulltext.]Nickel pincer catalyst proved to be excellent catalyst for the C-N cross-coupling reaction with the high turnover number (TON) for 1° and 2° amines and different nonactivated aryl halides under optimum conditions.
Albkuri, Yahya M.,RanguMagar, Ambar B.,Brandt, Andrew,Wayland, Hunter A.,Chhetri, Bijay P.,Parnell, Charlette M.,Szwedo, Peter,Parameswaran-Thankam, Anil,Ghosh, Anindya
p. 1669 - 1678
(2019/12/27)

Redox-Selective Iron Catalysis for α-Amino C-H Bond Functionalization via Aerobic Oxidation
Single-electron oxidation and α-deprotonation of tertiary anilines using Fe(phen)3(PF6)3 afford α-aminoalkyl radicals, which can be coupled with electrophilic partners to afford various tetrahydroquinolines. Mechanistically, the Fe(phen)n 2+/3+ catalytic cycle is maintained by O2 or a TBHP oxidant, and the presence of the oxygen bound iron complex, Fe(III)-OO(H), was elucidated by electron paramagnetic resonance and electrospray ionization mass spectrometry. This redox-selective nonheme iron catalyst behaves similarly to bioinspired heme iron catalysts.
Hwang, Joon Young,Ji, A. Young,Lee, Sang Hyeok,Kang, Eun Joo
supporting information
p. 16 - 21
(2019/11/11)

Visible-light-promoted radical cross-coupling of: Para-quinone methides with N-substituted anilines: An efficient approach to 2,2-diarylethylamines
An efficient protocol to access 2,2-diarylethylamines via visible-light-promoted radical reactions of para-quinone methides (p-QMs) with N-alkyl anilines has been disclosed. These reactions feature metal-free, redox-neutral, and mild reaction conditions with wide functional group compatibility.
Wu, Qiao-Lei,Guo, Jing,Huang, Gong-Bin,Chan, Albert S. C.,Weng, Jiang,Lu, Gui
supporting information
p. 860 - 864
(2020/02/15)

Continuous Synthesis of Aryl Amines from Phenols Utilizing Integrated Packed-Bed Flow Systems
Aryl amines are important pharmaceutical intermediates among other numerous applications. Herein, an environmentally benign route and novel approach to aryl amine synthesis using dehydrative amination of phenols with amines and styrene under continuous-flow conditions was developed. Inexpensive and readily available phenols were efficiently converted into the corresponding aryl amines, with small amounts of easily removable co-products (i.e., H2O and alkanes), in multistep continuous-flow reactors in the presence of heterogeneous Pd catalysts. The high product selectivity and functional-group tolerance of this method allowed aryl amines with diverse functional groups to be selectively obtained in high yields over a continuous operation time of one week.
Ichitsuka, Tomohiro,Kobayashi, Shū,Koumura, Nagatoshi,Sato, Kazuhiko,Takahashi, Ikko
supporting information
p. 15891 - 15896
(2020/07/13)

A simple method for the synthesis of sulfonic esters
An efficient and simple approach for the direct synthesis of aryl and heteroaryl sulfonic esters was developed using DMS and DES as alkoxysulfonylation reagents. The reaction is operationally simple and scalable. This protocol does not require solvent, expensive catalysts, base, ligand additives or other reagents. A wide range of sulfonic esters were synthesized in moderate to good chemical yields. This method has the advantage of low cost, facile and tolerated a wide range of substrates.
Bhatthula, Bharath Kumar Goud,Kanchani, Janardhan Reddy,Arava, Veera Reddy,Marata Chenna Subbarao, Subha
supporting information
p. 1 - 16
(2020/07/27)

Nickel-Catalyzed Amination of Aryl Thioethers: A Combined Synthetic and Mechanistic Study
Herein, we report a nickel-1,2-bis(dicyclohexylphosphino)ethane (dcype) complex for the catalytic Buchwald-Hartwig amination of aryl thioethers. The protocol shows broad applicability with a variety of different functional groups tolerated under the catalytic conditions. Extensive organometallic and kinetic studies support a nickel(0)-nickel(II) pathway for this transformation and revealed the oxidative addition complex as the resting state of the catalytic cycle. All the isolated intermediates have proven to be catalytically and kinetically competent catalysts for this transformation. The fleeting transmetalation intermediate has been successfully synthesized through an alternative synthetic organometallic pathway at lower temperature, allowing for in situ NMR study of the C-N bond reductive elimination step. This study addresses key factors governing the mechanism of the nickel-catalyzed Buchwald-Hartwig amination process, thus improving the understanding of this important class of reactions.
Bismuto, Alessandro,Delcaillau, Tristan,Müller, Patrick,Morandi, Bill
p. 4630 - 4639
(2020/05/19)

N-Methylation and Trideuteromethylation of Amines via Magnesium-Catalyzed Reduction of Cyclic and Linear Carbamates
A new reduction of carbamates to N-methyl amines is presented. The magnesium-catalyzed reduction reaction allows the conversion of cyclic and linear carbamates, including N-Boc protected amines, into the corresponding N-methyl amines and amino alcohols which are of significant interest due to their presence in many biologically active molecules. Furthermore, the reduction can be extended to the formation of N-trideuteromethyl labeled amines.
Magre, Marc,Szewczyk, Marcin,Rueping, Magnus
supporting information
p. 3209 - 3214
(2020/04/10)

1,2-Difunctionalization of Aryl Triflates: A Direct and Modular Access to Diversely Functionalized Anilines
ortho-Amino difunctionalization of aryl triflates has been achieved via a three-component reaction. The cascade reaction proceeds through a zincate base-mediated deprotonative formation of a reactive aryne intermediate, in situ nucleophilic addition, and coupling with electrophilic partners. This strategy leverages the advantageous reactivity of organozincate intermediates, enabling the installation of various functionalities such as amine, azide, oxygen, sulfur, halide, alkynyl, aryl, vinyl, and alkyl groups in a modular manner for the synthesis of diverse aniline skeletons.
Cho, Seoyoung,Wang, Qiu
supporting information

(2020/02/28)

Alkyl formates as reagents for reductive amination of carbonyl compounds
Alkyl formates in the presence of basic additives can serve as a reagent in the direct reductive amination of carbonyl compounds. The developed procedure can be applied to various aldehydes and ketones with electron donating and electron withdrawing groups.
Afanasyev, Oleg I.,Cherkashchenko, Ilia,Kuznetsov, Anton,Kliuev, Fedor,Semenov, Sergey,Chusova, Olga,Denisov, Gleb,Chusov, Denis
p. 112 - 113
(2020/03/03)

Transition-Metal-Free Three-Component Synthesis of Tertiary Aryl Amines from Nitro Compounds, Boronic Acids, and Trialkyl Phosphites
The synthesis of aromatic amines is of continuous interest in chemistry. An exceptionally versatile three-component reaction that directly transforms inexpensive nitro compounds, boronic acids, and trialkyl phosphites into tertiary aromatic amines has been realized. The reaction tolerates alkyl and aryl substituents on the nitro and boronic acid moieties, as well as functionalized phosphites. No transition-metal catalysis is required. The method is orthogonal to other classical metal-catalyzed syntheses since it tolerates the presence of halogens, and also permits the synthesis of functionalized compounds such as α-amino ester derivatives. (Figure presented.).
Roscales, Silvia,Csáky, Aurelio G.
supporting information
p. 111 - 117
(2019/11/16)

Tetracoordinate borates as catalysts for reductive formylation of amines with carbon dioxide
We report sodium trihydroxyaryl borates as the first robust tetracoordinate organoboron catalysts for reductive functionalization of CO2. These catalysts, easily synthesized from condensing boronic acids with metal hydroxides, activate main group element-hydrogen (E-H) bonds efficiently. In contrast to BX3 type boranes, boronic acids and metal-BAr4 salts, under transition metal-free conditions, sodium trihydroxyaryl borates exhibit high reactivity of reductive N-formylation toward a variety of amines (106 examples), including those with functional groups such as ester, olefin, hydroxyl, cyano, nitro, halogen, MeS-, ether groups, etc. The over-performance to catalyze formylation of challenging pyridyl amines affords a promising alternative method to the use of traditional formylation reagents. Mechanistic investigation supports electrostatic interactions as the key for Si/B-H activation, enabling alkali metal borates as versatile catalysts for hydroborylation, hydrosilylation, and reductive formylation/methylation of CO2.
Du, Chen-Xia,Huang, Zijun,Jiang, Xiaolin,Li, Yuehui,Makha, Mohamed,Wang, Fang,Zhao, Dongmei
p. 5317 - 5324
(2020/09/17)

Selective: N-formylation/N-methylation of amines and N-formylation of amides and carbamates with carbon dioxide and hydrosilanes: Promotion of the basic counter anions of the zinc catalyst
A catalyst composed of commercially available Zn(OAc)2 and 1,10-phenanthroline (phen) was effective in the N-formylation/N-methylation of amines using CO2 as the C1 source in the presence of hydrosilanes. An equimolar reaction of N-methylaniline with PhSiH3 under a CO2 atmosphere yielded the N-formylation product in 92% yield at 25 °C. Scale-up of the reaction using 10 mmol substrate was also successful in affording the desired product in 83% yield (1.1 g). This catalyst exhibits a high thermal stability and a turnover number (TON) of 385000 at 150 °C. In addition, the reaction of N-methylaniline in the presence of excess Ph2SiH2 produced N,N-dimethylaniline. Furthermore, our catalytic protocol was developed for the N-formylation of amides and carbamates, which have smaller pKa values and lower reactivities than the corresponding amines. The present Zn(OAc)2/phen catalyst was found to show versatility in the conversion of CO2 and amines into several functionalized organic chemicals under mild conditions. We propose that the basic counter anion (i.e., the acetate) of the catalyst activates both the Si-H and N-H bonds.
Zhang, Qiao,Lin, Xiao-Tao,Fukaya, Norihisa,Fujitani, Tadahiro,Sato, Kazuhiko,Choi, Jun-Chul
supporting information
p. 8414 - 8422
(2020/12/29)

Selective reduction of formamides to O-silylated hemiaminals or methylamines with HSiMe2Ph catalyzed by iridium complexes
The reaction of (4-methyl-pyridin-2-iloxy)ditertbutylsilane (NSitBu-H, 1) with [IrCl(coe)2]2 affords the iridium(iii) complex [Ir(H)(Cl)(κ2-NSitBu)(coe)] (2), which has been fully characterized including X-ray diffraction studies. The reaction of 2 with AgCF3SO3 leads to the formation of species [Ir(H)(CF3SO3)(κ2-NSitBu)(coe)] (3). The iridium complexes 2 and 3 are effective catalysts for the reduction of formamides with HSiMe2Ph. The selectivity of the reduction process depends on the catalyst. Thus, by using complex 2, with a chloride ancillary ligand, it has been possible to selectively obtain the corresponding O-silylated hemiaminal by reaction of formamides with one equivalent of HSiMe2Ph, while complex 3, with a triflate ligand instead of chloride, catalyzed the selective reduction of formamides to the corresponding methylamine.
Guzmán, Jefferson,Bernal, Ana M.,García-Ordu?a, Pilar,Lahoz, Fernando J.,Oro, Luis A.,Fernández-Alvarez, Francisco J.
p. 4255 - 4262
(2019/04/01)

Palladium nanoparticles supported on cysteine-functionalized MNPs as robust recyclable catalysts for fast O- and N-arylation reactions in green media
A magnetically robust recyclable nanocatalyst was fabricated by immobilizing of Pd onto the surface of cysteine-functionalized magnetic nanoparticles (MNPs?Cys-Pd). This nanocatalyst was characterized using various techniques such as FT-IR, XRD, TEM, SEM, EDX, VSM, and ICP. The application of catalyst (MNPs?Cys-Pd) was investigated for O-arylation and N-arylation reactions. This phosphine-free complex was found as highly efficient heterogeneous catalyst in green media and mild reaction conditions. In addition, it gave excellent recyclability without significant deactivation after ten cycles.
Hajipour, Abdol R.,Khorsandi, Zahra,Fatemeh Mohammadi Metkazini
(2019/08/12)

Direct Installation of a Silyl Linker on Ready-Made NHC Ligands: Immobilized NHC-Pd Complex for Buchwald-Hartwig Amination
An immobilized N-heterocyclic carbene (NHC)-Pd complex was prepared via direct silyl linker installation onto the imidazole backbone of commercially available 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) ligand. The IPr backbone was lithiated and treated with Me2SiCl2 to afford ClMe2Si-IPr, which reacted with [Pd(π-allyl)Cl]2 to yield a ClMe2Si-IPr-Pd complex, and this was immobilized on Wang resin. The immobilized NHC-Pd complex facilitated quantitative Buchwald-Hartwig amination of aryl chlorides within 10 min, even at a low Pd loading of 0.2 mol %. The catalyst could be removed from the reaction mixture by simple filtration, and Pd leaching into the reaction medium was suppressed to below 1 ppm.
Mizusaki, Tomoteru,Matsumoto, Kazuhiro,Takeuchi, Katsuhiko,Fukaya, Norihisa,Takagi, Yukio,Choi, Jun-Chul
supporting information
p. 1872 - 1876
(2019/05/07)

A Highly Active Ylide-Functionalized Phosphine for Palladium-Catalyzed Aminations of Aryl Chlorides
Ylide-functionalized phosphine ligands (YPhos) were rationally designed to fit the requirements of Buchwald–Hartwig aminations at room temperature. This ligand class combines a strong electron-donating ability comparable to NHC ligands with high steric demand similar to biaryl phosphines. The active Pd species are stabilized by agostic C?H???Pd rather than by Pd–arene interactions. The practical advantage of YPhos ligands arises from their easy and scalable synthesis from widely available, inexpensive starting materials. Benchmark studies showed that YPhos-Pd complexes are superior to the best-known phosphine ligands in room-temperature aminations of aryl chlorides. The utility of the catalysts was demonstrated by the synthesis of various arylamines in high yields within short reaction times.
Weber, Philip,Scherpf, Thorsten,Rodstein, Ilja,Lichte, Dominik,Scharf, Lennart T.,Goo?en, Lukas J.,Gessner, Viktoria H.
supporting information
p. 3203 - 3207
(2019/01/09)

[Pd(4-R3Si-IPr)(allyl)Cl], a Family of Silyl-Substituted Pd-NHC Complexes: Catalytic Systems for the Buchwald-Hartwig Amination
A family of Pd-IPr complexes (1Pd-6Pd) featuring electropositive and bulky R3Si substituents at the 4-position of the NHC ring was prepared and fully characterized. The catalytic performance of 1Pd (R3Si = SiMe3) and 3Pd (R3Si = Si(allyl)Me2) in the Buchwald-Hartwig amination was excellent, notably outperforming those of other previously reported catalytic systems by requiring shorter reaction times, lower catalyst loadings, and milder reaction conditions. Furthermore, a systematic evaluation of both the electronic and steric influences of the 4-R3Si-IPr ligand on the overall catalytic performance of 1Pd-6Pd revealed that electronic rather than steric factors play a dominant role.
Fukaya, Norihisa,Mizusaki, Tomoteru,Hatakeyama, Kouhei,Seo, Yuto,Inaba, Yuuya,Matsumoto, Kazuhiro,Lee, Vladimir Ya.,Takagi, Yukio,Kuwabara, Junpei,Kanbara, Takaki,Choe, Yoong-Kee,Choi, Jun-Chul
p. 375 - 384
(2019/01/11)

Endergonic addition of N -methylamines to aromatic ketones driven by photochemical offset of the entropic cost
Intermolecular addition reactions are generally accompanied by an entropic penalty due to the decrease of molecular numbers during the reaction, which sometimes makes the reaction endergonic. Here we demonstrate that such an endergonic reaction can be promoted with light-energy as a driving force; N-methylamines were added to aromatic ketones to produce aminoalcohols under UV-light irradiation. The reaction represents an obvious example showing that the photochemical approach is effective to offset such an entropic cost, and thereby to drive thermodynamically uphill addition reactions. Moreover the present reactions are highly expedient from the synthetic view point, being transition-metal-catalyst-free, scalable, highly atom economical, and regioselective. The product amines can be converted in one step to functional multi-arylated enamines, which are potentially valuable compounds in electronic materials.
Iwamoto, Takahiro,Hosokawa, Atsushi,Nakamura, Masaharu
supporting information
p. 11683 - 11686
(2019/10/02)

Three-Component Aminoselenation of Arynes
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.
supporting information
p. 9613 - 9617
(2019/11/28)

Ullmann-type: N-arylation of anilines with alkyl(aryl)sulfonium salts
A palladium/copper-cocatalyzed Ullmann-type N-arylation of anilines using alkyl(aryl)sulfonium triflates as arylation reagents has been accomplished. The reaction enabled Caryl-S bond cleavage over Calkyl-S bond breakage of alkyl(aryl)sulfoniums by Pd(P(tBu)3)2/CuI and gave the corresponding N-arylated products in good to high yields. It was also significant that the reactions of aniline with asymmetric butyl(mesityl)(aryl)sulfonium triflates showed excellent selectivity, in which the aryl groups other than the bulky and electron-rich mesityl moieties were transformed.
Tian, Ze-Yu,Zhang, Cheng-Pan
supporting information
p. 11936 - 11939
(2019/10/11)

Highly-chemoselective step-down reduction of carboxylic acids to aromatic hydrocarbons: Via palladium catalysis
Aryl carboxylic acids are among the most abundant substrates in chemical synthesis and represent a perfect example of a traceless directing group that is central to many processes in the preparation of pharmaceuticals, natural products and polymers. Herein, we describe a highly selective method for the direct step-down reduction of carboxylic acids to arenes, proceeding via well-defined Pd(0)/(ii) catalytic cycle. The method shows a remarkably broad substrate scope, enabling to direct the classical acyl reduction towards selective decarbonylation by a redox-neutral mechanism. The utility of this reaction is highlighted in the direct defunctionalization of pharmaceuticals and natural products, and further emphasized in a range of traceless processes using removable carboxylic acids under mild, redox-neutral conditions orthogonal to protodecarboxylation. Extensive DFT computations were conducted to demonstrate preferred selectivity for the reversible oxidative addition and indicated that a versatile hydrogen atom transfer (HAT) pathway is operable.
Liu, Chengwei,Qin, Zhi-Xin,Ji, Chong-Lei,Hong, Xin,Szostak, Michal
p. 5736 - 5742
(2019/06/18)

Palladium-Catalyzed C(sp2)-N Bond Cross-Coupling with Triaryl Phosphates
The first general palladium-catalyzed amination of aryl phosphates is described. The combination of MorDalPhos with [Pd(?-cinnamyl)Cl]2 enables the amination of electron-rich, electron-neutral, and electron-poor aryl phosphates with a board range of aromatic, aliphatic, and heterocyclic amines. Common functional groups such as ether, keto, ester, and nitrile show an excellent compatibility in this reaction condition. The solvent-free amination reactions are also successful in both solid coupling partners. The gram-scale cross-coupling is achieved by this catalytic system.
Chen, Zicong,Chen, Xiangmeng,So, Chau Ming
supporting information
p. 6366 - 6376
(2019/05/24)

Palladium-catalyzed c(sp2)-n bond cross-coupling with triaryl phosphates
The first general palladium-catalyzed amination of aryl phosphates is described. The combination of MorDalPhos with [Pd(-cinnamyl)Cl]2 enables the amination of electron-rich, electron-neutral, and electron-poor aryl phosphates with a board range of aromatic, aliphatic, and heterocyclic amines. Common functional groups such as ether, keto, ester, and nitrile show an excellent compatibility in this reaction condition. The solvent-free amination reactions are also successful in both solid coupling partners. The gram-scale cross-coupling is achieved by this catalytic system.
Chen, Zicong,Chen, Xiangmeng,So, Chau Ming
(2019/05/22)

Air-tolerant direct reductive N-methylation of amines using formic acid via simple inorganic base catalysis
The construction of N-methyl amine moieties is an important reaction that has found numerous applications. Development of new methylation agents that are more environmentally benign than classical agents, such as iodomethane and methyl sulfate, is still highly desirable. Herein, we report a convenient protocol for direct reductive N-methylation of amines using formic acid as the methylation agent via simple inorganic base catalysis. The present protocol operates under transition-metal-free and air-tolerant conditions. Both the catalyst, K2HPO4, and the reductant, polymethylhydrosiloxane (PMHS), are cheap and easily separable from the crude reaction product mixture. Mechanistic investigations suggest that the reaction occur through the formation of an acetal intermediate followed by the C–N bond formation.
Huang, Yan,Deng, Wei,Lin, Bo-Lin
supporting information

(2019/05/29)

Mn-Catalyzed Selective Double and Mono-N-Formylation and N-Methylation of Amines by using CO2
Functionalization of amines by using CO2 is of fundamental importance considering the abundance of amines and CO2. In this context, the catalytic formylation and methylation of amines represent convenient and successful protocols for selective CO2 utilization as a C1 building block. This study represents the first example of selective catalytic double N-formylation of aryl amines by using a dinuclear Mn complex in the presence of phenylsilane. This robust system also allows for selective formylation and methylation of amines under a range of conditions.
Huang, Zijun,Jiang, Xiaolin,Zhou, Shaofang,Yang, Peiju,Du, Chen-Xia,Li, Yuehui
p. 3054 - 3059
(2019/04/10)

UiO-type metal-organic frameworks with NHC or metal-NHC functionalities for: N-methylation using CO2 as the carbon source
We demonstrate the first metal-organic framework (MOF) that catalyzes N-methylation of amines using 1 atm CO2 and phenylsilane under ambient conditions. Compared with its homogeneous analog, the incorporation of N-heterocyclic carbene (NHC) into the MOF provides more efficient catalysis with improved reaction kinetics, turnover numbers and recyclability. Moreover, the metalated NHC functionalized MOF achieves direct N-methylation of amines bearing carboxylate moieties, which are common building blocks in pharmaceutical chemistry.
Zhang, Xu,Jiang, Yilin,Fei, Honghan
supporting information
p. 11928 - 11931
(2019/10/11)

Selective formylation or methylation of amines using carbon dioxide catalysed by a rhodium perimidine-based NHC complex
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.
supporting information
p. 538 - 549
(2019/02/14)

Biomass-derived N-doped porous carbon: An efficient metal-free catalyst for methylation of amines with CO2
Developing green, efficient, and low-cost catalysts for methylation of N-H by using CO2 as the C1 resource is highly desired yet remains a significant challenge. Herein, N-doped porous carbons (NPCs) were designed, synthesized, and proved to be an excellent metal-free catalyst for CO2-participated methylation conversion. NPCs were prepared via the pyrolysis of a mixture of tannic acid and urea. Both theoretical calculation and experiment demonstrate that the N species especially pyridinic N and pyrrolic N within NPCs can work as Lewis basic sites for attacking CO2 to weaken the CO bonds and lower the molecule conversion barrier, facilitating the subsequent methylation of N-H to produce, for example, N,N-dimethylaniline. Besides, the unique porous structure can enrich CO2 and accelerate mass transfer, synergistically promoting the conversion of CO2. The optimized NPC(1/5) catalyst, integrating the porous structure and strong Lewis basicity, exhibits excellent catalytic activity for CO2-based methylation reaction under mild conditions (1 bar CO2, 75 °C). Our work, for the first time, demonstrates the feasibility of using NPCs to catalyze the methylation of amino compounds to produce N,N-dimethylamine by exploiting CO2 as the C1 resource.
Tang, Feiying,Wang, Liqiang,Liu, You-Nian
supporting information
p. 6252 - 6257
(2019/12/03)

Nickel-catalyzed N-arylation of amines with arylboronic acids under open air
In this study, a well-defined, novel NHC-Ni complex was developed and used to catalyze the N-arylation of alkyl- and arylamines with arylboronic acids in a rare version of Chan-Lam coupling. Although the same coupling using copper catalysts has been widely studied, the nickel-catalyzed version is rare and normally requires 10–20 mol% catalyst loading. This novel NHC-Ni complex in combination with 4,4′-dimethyl-2,2′-bipyridine, however, proved to be an effective catalyst that lowered the required catalyst loading to only 2.0 mol%.
Ando, Shin,Hirota, Yurina,Matsunaga, Hirofumi,Ishizuka, Tadao
supporting information
p. 1277 - 1280
(2019/04/10)

A mechanical to urge the enters the carbon - [...] forming method (by machine translation)
The invention discloses a mechanical to urge the enters the carbon - [...] forming method, said method comprising: in order to type 2 shown in formulae of organic amine 3 shown the chlorinated aromatic hydrocarbon as the raw material, the catalyst, ligand, in the presence of alkali and additive, the reaction is carried out by the mechanical grinding method, after the reaction mixture after the separation and purification, obtains the type 1 compound shown; in the present invention relates to mechanical grinding promotion to the chlorinated aromatic hydrocarbon as the substrate of the Buchwald - Hartwig reaction mainly adopts the organic phosphonate ligands, in the palladium catalyst under the action of the organic amine compound with the chlorinated aromatic hydrocarbon of the between the coupling, so as to obtain high yield of the target product, the majority of the reaction can be 90% or more yield. The mild reaction conditions, can be in the 1 - 2 H to complete the reaction. (by machine translation)
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Paragraph 0042; 0043; 0044; 0046; 0048

(2018/09/21)

[Pd(IPr*R)(acac)Cl]: Efficient bulky Pd-NHC catalyst for Buchwald-Hartwig C-N cross-coupling reaction
A series of bulky palladium catalysts based on N-heterocyclic carbene, (Pd(NHC)(acac)Cl: NHC = IPr*me = N,N′-bis(2,6-bis(di-p-tolylmethyl)-4-methylphenyl)-imidazol-2 -ylidene, Pd(IPr*me)(acac)Cl; NHC = IPr*ipr = N,N′-bis(2,6-bis(di-4-isopropylphenyl)-4-methylphenyl)-imidazol-2 -ylidene, Pd(IPr*ipr)(acac)Cl; and NHC = IPr*tBu = N,N′-bis(2,6-bis(di-4-(tert-butyl)phenyl)- 4-methylphenyl)- imidazol-2-ylidene, Pd(IPr*tBu)(acac)Cl; acac = acetylacetonate), have been designed and synthesized. These three new catalysts showed much better catalytic activity in the Buchwald?Hartwig arylamination coupling reaction as compare to the earlier congener (IPr*)Pd(acac)Cl (IPr* = N,N′-bis(2,6-diphenylmethyl)-4-methylphenylimidazol-2-ylidene). The highly active PdII precatalyst [Pd(IPr*me)(acac)Cl] has been fully explored by using a wide range of substrates with different electronic and steric demands of coupling partners, for which up to 99% isolated yields were obtained. Remarkably, the moderate isolated yield was obtained for the challenging coupling of the amine bearing very bulky groups.
Tian, Xiabing,Lin, Jing,Zou, Sheng,Lv, Junwei,Huang, Qingfei,Zhu, Jin,Huang, Shuping,Wang, Qiwei
supporting information
p. 125 - 130
(2018/03/06)

Solvent-free mechanochemical Buchwald-Hartwig amination of aryl chlorides without inert gas protection
A solvent-free Buchwald-Hartwig amination had been developed under high-speed ball-milling conditions, which afforded the desired products with moderate to high yields. The addition of sodium sulfate was found to be crucial for improving both the performance and the reproducibility. Comparative solvent-free stirring experiments implicated the importance of mechanical interaction for the transformation, and the inert gas was proved to be unnecessary for this amination.
Shao, Qiao-Ling,Jiang, Zhi-Jiang,Su, Wei-Ke
supporting information
p. 2277 - 2280
(2018/05/16)

NOVEL HYDRAZIDE CONTAINING COMPOUNDS AS BTK INHIBITORS
The present invention relates to novel hydrazide containing compounds as Bruton tyrosine kinase inhibitors, process of preparation thereof, and to the use of the compounds in the preparation of pharmaceutical compositions for the therapeutic treatment of disorders involving mediation of Bruton tyrosine kinase in humans.
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Paragraph 38

(2018/02/03)

Synthesis method of N-methylamine compound
The invention discloses a synthesis method of an N-methylamine compound. The synthesis method is characterized in that a carbamyl imidazole compound is used as a raw material; a NaBH4/I2 is used for performing backflow in tetrahydrofuran to prepare an N-methyl structure compound. The used reduction system NaBH4/I2 has the advantages of environment-friendly effect, performance stability, high conversion rate and the like. The synthesis method has the beneficial effects that (1) the synthesis method has wide applicability; amine can be used as the raw material; carboxylic acid can also be used as the raw material; (2) the product yield is high and reaches as high as 82 percent; (3) a synthetic agent is simple and can be easily obtained; the cost is low; the process is simple; the reaction conditions are mild; the synthesis method is suitable for industrial production. A concrete reaction formula is shown in the description, wherein R1 and R2 are identical or different atoms or groups, and are respectively and independently selected from one of hydrogen atoms, C1-C20 straight-chain or branch-chain alkane, C5-C10 naphthenic groups, aryl groups and substituted aryl groups; monosubstitution or multi-substitution is performed on aromatic rings of the substituted aryl groups. In addition, KBH4 is also applicable to the reaction.
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Paragraph 0059-0062

(2018/09/08)

Photoinduced Cross-Coupling of Amines with 1,2-Diiodobenzene and Its Application in the Synthesis of Carbazoles
A facile and efficient process for the preparation of various tertiary aminobenzenes and carbazole derivatives via photoinduced cross-coupling of amines with 1,2-diiodobenzene is reported. Mechanistic investigations indicate that the transformation proceeds via nucleo-philic addition of an amine to the benzyne intermediate accompanied with a proton transfer process, followed by an oxidative cyclization of the generated diphenylamine to furnish the corresponding carbazole products.
Zhao, Xinxin,Chen, Ming,Huang, Binbin,Yang, Chao,Gao, Yuan,Xia, Wujiong
p. 2981 - 2989
(2018/05/15)

Potassium tert-butoxide-mediated generation of arynes from o-bromoacetophenone derivatives
o-bromoacetophenone derivatives as new versatile aryne precursors are induced to selectively eliminate the CAr–Br and CAr–C(Ac) bonds in the help of t-BuOK. Furthermore, the active aryne intermediates are successfully appl
Chang, Denghu,Gao, Fei,Shi, Lei
p. 2428 - 2434
(2018/04/24)

Direct arylation of tertiary amines via aryne intermediates using diaryliodonium salts
With a strategy by using diaryliodonium salts as the precursors of benzynes, direct N-arylation of tertiary amines with diaryliodonium salts was reported. Thus, the desired aromatic tertiary amines with a wide range of substituents were synthesized in moderate to excellent yields of 55–91%.
Zhang, Zhiang,Wu, Xunshen,Han, Jianwei,Wu, Wenjun,Wang, Limin
supporting information
p. 1737 - 1741
(2018/04/02)

Palladium-catalyzed amination of aryl sulfoxides
Amination of diaryl sulfoxides with anilines and alkylamines has been accomplished under palladium/N-heterocyclic carbene (NHC) catalysis. Owing to its electron deficiency, the leaving arenesulfenate anion would be smoothly released from the palladium center to result in uneventful catalyst turnover under milder reaction conditions in comparison with previous C-S bond amination reactions. This amination accommodated a wider range of functional groups such as silyl, boryl, methylsulfanyl, and halogen moieties. Regioselective amination of unsymmetrical diaryl sulfoxides was also executed by means of steric bias.
Yoshida, Yuto,Otsuka, Shinya,Nogi, Keisuke,Yorimitsu, Hideki
supporting information
p. 1134 - 1137
(2018/02/23)