- Iridium/graphene nanostructured catalyst for the: N -alkylation of amines to synthesize nitrogen-containing derivatives and heterocyclic compounds in a green process
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A facile iridium/graphene-catalyzed methodology providing an efficient synthetic route for C-N bond formation is reported. This catalyst can directly promote the formation of C-N bonds, without pre-activation steps, and without solvents, alkalis and other additives. This protocol provides a direct N-alkylation of amines using a variety of primary and secondary alcohols with good selectivity and excellent yields. Charmingly, the use of diols resulted in intermolecular cyclization of amines, and such products are privileged structures in biologically active compounds. Two examples illustrate the advantages of this catalyst in organic synthesis: the tandem catalysis to synthesize hydroxyzine, and the intermolecular cyclization to synthesize cyclizine. Water is the only by-product, which makes this catalytic process sustainable and environmentally friendly. This journal is
- Chen, Tsun-Ren,Chen, Yi-Sheng,Chen, Yu-Tung,Lee, Wen-Jen,Lin, Yen-Hsing,Wang, Hao-Chen
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p. 4760 - 4770
(2022/02/21)
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- Hydroborative reduction of amides to amines mediated by La(CH2C6H4NMe2-: O)3
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The deoxygenative reduction of amides to amines is a great challenge for resonance-stabilized carboxamide moieties, although this synthetic strategy is an attractive approach to access the corresponding amines. La(CH2C6H4NMe2-o)3, a simple and easily accessible lanthanide complex, was found to be highly efficient not only for secondary and tertiary amide reduction, but also for the most challenging primary reduction with pinacolborane. This protocol exhibited good tolerance for many functional groups and heteroatoms, and could be applied to gram-scale synthesis. The active species in this catalytic cycle was likely a lanthanide hydride.
- Gong, Mingliang,Guo, Chenjun,Luo, Yunjie,Xie, Hongzhen,Zhang, Fangcao
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p. 779 - 791
(2022/01/22)
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- BF3·Et2O as a metal-free catalyst for direct reductive amination of aldehydes with amines using formic acid as a reductant
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A versatile metal- and base-free direct reductive amination of aldehydes with amines using formic acid as a reductant under the catalysis of inexpensive BF3·Et2O has been developed. A wide range of primary and secondary amines and diversely substituted aldehydes are compatible with this transformation, allowing facile access to various secondary and tertiary amines in high yields with wide functional group tolerance. Moreover, the method is convenient for the late-stage functionalization of bioactive compounds and preparation of commercialized drug molecules and biologically relevant N-heterocycles. The procedure has the advantages of simple operation and workup and easy scale-up, and does not require dry conditions, an inert atmosphere or a water scavenger. Mechanistic studies reveal the involvement of imine activation by BF3and hydride transfer from formic acid.
- Fan, Qing-Hua,Liu, Xintong,Luo, Zhenli,Pan, Yixiao,Xu, Lijin,Yang, Ji,Yao, Zhen,Zhang, Xin
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supporting information
p. 5205 - 5211
(2021/07/29)
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- Reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3as a reductant
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Herein, we report the first example of efficient reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3 as a catalyst and a reductant under mild conditions, affording various tertiary and secondary amines in excellent yields. A mechanistic study indicates that BH3N(C2H5)3 plays a dual function role of promoting imine and iminium formation and serving as a reductant in reductive amination. This journal is
- Zou, Qizhuang,Liu, Fei,Zhao, Tianxiang,Hu, Xingbang
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supporting information
p. 8588 - 8591
(2021/09/04)
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- Visible-Light-Driven Stereoselective Annulation of Alkyl Anilines and Dibenzoylethylenes via Electron Donor-Acceptor Complexes
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A catalyst-free, stereoselective visible-light-driven annulation reaction between alkenes and N,N-substituted dialkyl anilines for the synthesis of substituted tetrahydroquinolines is presented. The reaction is driven by the photoexcitation of an electron donor-acceptor (EDA) complex, and the resulting products are obtained in good to high yields with complete diastereoselectivity. Mechanistic rationale and photochemical characterization of the EDA-complex are provided.
- Runemark, August,Zacharias, Savannah C.,Sundén, Henrik
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p. 1901 - 1910
(2021/02/05)
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- Dirhodium-Catalyzed Chemo-and Site-Selective C-H Amidation of N, N-Dialkylanilines
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A method for dirhodium-catalyzed C(sp 3)-H amidation of N, N-dimethylanilines was developed. Chemoselective C(sp 3)-H amidation of N-methyl group proceeded exclusively in the presence of C(sp 2)-H bonds of the electron-rich aromatic ring. Site-selective C(sp 3)-H amidation proceeded exclusively at the N-methyl group of N-methyl-N-Alkylaniline derivatives with secondary, tertiary, and benzylic C(sp 3)-H bonds α to a nitrogen atom.
- Chen, Gong,Arai, Kenta,Morisaki, Kazuhiro,Kawabata, Takeo,Ueda, Yoshihiro
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supporting information
p. 728 - 732
(2021/01/18)
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- Visible light-induced N-methyl activation of unsymmetric tertiary amines
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In the presence of methylene group, selective N-methyl activation of tertiary amines has been accomplished with the aid of visible light using organic photocatalyst under air. This protocol explores numerous aliphatic and aromatic substituted tetra-hydroquinoline analogues from various tertiary amines and maleimides. Furthermore, this approach was applied to activate the methyl group of N-methyl carbazole to generate the biologically active molecule.
- Perumal, Gopi,Kandasamy, Mohanraj,Ganesan, Balaji,Govindan, Karthick,Sathya, Harsha,Hung, Min-Yuan,Chandru Senadi, Gopal,Wu, Ya-Ching,Lin, Wei-Yu
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supporting information
(2021/01/09)
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- A Photocatalytic Regioselective Direct Hydroaminoalkylation of Aryl-Substituted Alkenes with Amines
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A photocatalytic method for the α-selective hydroaminoalkylation of cinnamate esters has been developed. The reaction involves the regioselective addition of α-aminoalkyl radicals generated from aniline derivatives or aliphatic amines to the α-position of unsaturated esters. The scope of aromatic alkenes was extended to styrenes undergoing hydroaminoalkylation with anti-Markovnikov selectivity, which confirms the importance of the aromatic group at the β-position. Simple scale-up is demonstrated under continuous flow conditions, highlighting the practicality of the method.
- Larionova, Natalia A.,Ondozabal, Jun Miyatake,Smith, Emily G.,Cambeiro, Xacobe C.
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supporting information
p. 5383 - 5388
(2021/07/26)
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- Two-Step Protocol for Iodotrimethylsilane-Mediated Deoxy-Functionalization of Alcohols
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We have developed a two-step protocol for iodotrimethylsilane-mediated deoxy-functionalization of primary and secondary alcohols to afford products containing a C?N, C?S, or C?O bond. In the first step the alcohol undergoes iodination with iodotrimethylsilane, and in the second, the iodine atom is replaced by a N, S, or O nucleophile. Compared with traditional Mitsunobu reaction, non-acidic pre-nucleophiles can be used, and the reaction proceeds with retention of configuration. This operationally simple, highly efficient protocol can be used for some natural products and small-molecule drugs containing hydroxy-group.
- Chen, Yuming,He, Ru,Song, Hongjian,Yu, Guoqing,Li, Chenglin,Liu, Yuxiu,Wang, Qingmin
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supporting information
p. 1179 - 1183
(2021/02/01)
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- Fe(III)-catalyzed Oxidative Povarov Reaction with Molecular Oxygen Oxidant
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The synthesis of tetrahydroquinoline derivatives from dimethyl anilines and enamides has been developed by Fe(III)-phenanthroline complex under aerobic condition. The oxidation of tertiary anilines involving a single electron transfer of Fe(phen)3(PF6)3 afforded the iminium ion intermediate, which reacted with electron-rich alkenes to build a six-membered N-heterocycles containing quaternary carbon center via the oxidative Povarov reaction process.
- Park, Du Yong,Hwang, Joon Young,Kang, Eun Joo
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supporting information
p. 798 - 801
(2021/04/09)
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- 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
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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
-
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- CO2-tuned highly selective reduction of formamides to the corresponding methylamines
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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
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supporting information
p. 7534 - 7538
(2021/10/12)
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- Visible-Light-Induced C(sp2)-C(sp3) Cross-Dehydrogenative-Coupling Reaction of N-Heterocycles with N-Alkyl- N-methylanilines under Mild Conditions
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Disclosed herein is a cross-dehydrogenative-coupling reaction of N-heterocycles including 1,2,4-triazine-3,5(2H, 4H)-diones and quinoxaline-2(1H)-ones with N-methylanilines to form C(sp2)-C(sp3) under visible-light illumination and ambient air at room temperature. In this process, easily available Ru(bpy)3Cl2·6H2O serves as the catalyst, and air acts as the green oxidant. This method features high atom economy, environmental friendliness, and convenient operation and provides an efficient and practical access to aminomethyl-substituted N-heterocycles with extensive functional group compatibility in 40-86% yields.
- Zhang, Hong-Yu,Chen, Jianjun,Lu, Cong-Cong,Han, Ya-Ping,Zhang, Yuecheng,Zhao, Jiquan
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p. 11723 - 11735
(2021/09/02)
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- Reduction of Amides to Amines with Pinacolborane Catalyzed by Heterogeneous Lanthanum Catalyst La(CH2C6H4NMe2- o)3@SBA-15
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Hydroboration of amides is a useful synthetic strategy to access the corresponding amines. In this contribution, it was found that the supported lanthanum benzyl material La(CH2C6H4NMe2-o)3@SBA-15 was highly active for the hydroboration of primary, secondary, and tertiary amides to amines with pinacolborane. These reactions selectively produced target amines and showed good tolerance for functional groups such as -NO2, -halogen, and -CN, as well as heteroatoms such as S and O. This reduction procedure exhibited the recyclable and reusable property of heterogeneous catalysts and was applicable to gram-scale synthesis. The reaction mechanisms were proposed based on some control experiments and the previous literature. This is the first example of hydroborative reduction of amides to amines mediated by heterogeneous catalysts.
- Guo, Chenjun,Zhang, Fangcao,Yu, Chong,Luo, Yunjie
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supporting information
p. 13122 - 13135
(2021/08/31)
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- Switching between mono and doubly reduced odd alternant hydrocarbon: designing a redox catalyst
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Since the early Hückel molecular orbital (HMO) calculations in 1950, it has been well known that the odd alternant hydrocarbon (OAH), the phenalenyl (PLY) system, can exist in three redox states: closed shell cation (12π e?), mono-reduced open shell neutral radical (13π e?) and doubly reduced closed shell anion (14π e?). Switching from one redox state of PLY to another leads to a slight structural change owing to its low energy of disproportionation making the electron addition or removal process facile. To date, mono-reduced PLY based radicals have been extensively studied. However, the reactivity and application of doubly reduced PLY species have not been explored so far. In this work, we report the synthesis of the doubly reduced PLY species (14π e?) and its application towards the development of redox catalysisviaswitching with the mono-reduced form (13π e?) for aryl halide activation and functionalization under transition metal free conditions without any external stimuli such as heat, light or cathodic current supply.
- Ahmed, Jasimuddin,Datta, Paramita,Das, Arpan,Jomy, Stephy,Mandal, Swadhin K.
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p. 3039 - 3049
(2021/03/14)
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- Synthesis ofN-aryl amines enabled by photocatalytic dehydrogenation
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Catalytic dehydrogenation (CD)viavisible-light photoredox catalysis provides an efficient route for the synthesis of aromatic compounds. However, access toN-aryl amines, which are widely utilized synthetic moieties,viavisible-light-induced CD remains a significant challenge, because of the difficulty in controlling the reactivity of amines under photocatalytic conditions. Here, the visible-light-induced photocatalytic synthesis ofN-aryl amines was achieved by the CD of allylic amines. The unusual strategy using C6F5I as an hydrogen-atom acceptor enables the mild and controlled CD of amines bearing various functional groups and activated C-H bonds, suppressing side-reaction of the reactiveN-aryl amine products. Thorough mechanistic studies suggest the involvement of single-electron and hydrogen-atom transfers in a well-defined order to provide a synergistic effect in the control of the reactivity. Notably, the back-electron transfer process prevents the desired product from further reacting under oxidative conditions.
- Kim, Jungwon,Kim, Siin,Choi, Geunho,Lee, Geun Seok,Kim, Donghyeok,Choi, Jungkweon,Ihee, Hyotcherl,Hong, Soon Hyeok
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p. 1915 - 1923
(2021/02/22)
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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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- Half-Sandwich Ru(II) Complexes with N,O-Chelate Ligands: Diverse Catalytic Activity for Amine Synthesis in Water
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Several types of β-ketoamino based N,O-coordinate half-sandwich ruthenium complexes have been synthesized in moderate to good yields. The stable ruthenium complexes displayed good and diverse catalytic efficiency in reductive amination between aldehydes and amines in aqueous solution. The method gave a facile route for one-pot synthesis of diverse complicated amines with a low catalyst loading by using cheap and less-toxic HCOOH or clean H2 as hydrogen source. Catalyst Ru1 showed the highest catalytic activity of 190 h-1 TOF value in the reductive amination reaction of benzaldehyde with aniline. The corresponding amine products were furnished in excellent yields under the standard catalysis system. The efficient and diverse catalytic activity, broad substance scope, mild conditions, and environmentally benign solvent made this system potentially applicable in industrial production. Ruthenium complexes were characterized using NMR, elemental analysis, and IR techniques to confirm their structure.
- Yun, Xue-Jing,Ling, Chun,Deng, Wei,Liu, Zhen-Jiang,Yao, Zi-Jian
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p. 3830 - 3838
(2020/11/13)
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- Thioglycerol-Stabilized Rhodium Nanoparticles in Biphasic Medium as Catalysts in Multistep Reactions
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Small rhodium nanoparticles (ca. 3.5 nm) were prepared by the decomposition of an organometallic precursor under hydrogen pressure in glycerol using 1-thioglycerol as stabilizer. Full characterization in the solid state [HR-TEM, EDX, XPS] showed a fcc structure for the Rh0/RhI nanoparticles capped with thiolate ligand. Reduction of different functionalities, including nitro groups and imines, was applied to tandem reductive amination of aldehydes with primary and secondary amines, and to the synthesis of N-substituted anilines from nitrobenzene. In addition, thiolate-capped RhNPs could be recovered and reused up to 5 runs without loss of activity nor selectivity.
- Guerrero-Ríos, Itzel,Portales-Martínez, Benjamín,Reina, Antonio,Serrano-Maldonado, Alejandro
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supporting information
(2020/07/04)
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- ROMP-Boranes as Moisture-Tolerant and Recyclable Lewis Acid Organocatalysts
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Although widely used in catalysis, the multistep syntheses and high loadings typically employed are limiting broader implementation of highly active tailor-made arylborane Lewis acids and Lewis pairs. Attempts at developing recyclable systems have thus far met with limited success, as general and versatile platforms are yet to be developed. We demonstrate a novel approach that is based on the excellent control and functional group tolerance of ring-opening metathesis polymerization (ROMP). The ROMP of highly Lewis acidic borane-functionalized phenylnorbornenes afforded both a soluble linear copolymer and a cross-linked organogel. The polymers proved highly efficient as recyclable catalysts in the reductive N-alkylation of arylamines under mild conditions and at exceptionally low catalyst loadings. The modular design presented herein can be readily adapted to other finely tuned triarylboranes, enabling wide applications of ROMP-borane polymers as well-defined supported organocatalysts.
- Vidal, Fernando,McQuade, James,Lalancette, Roger,J?kle, Frieder
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supporting information
p. 14427 - 14431
(2020/10/13)
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- Regioselective, Photocatalytic α-Functionalization of Amines
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Photocatalytic α-functionalization of amines provides a mild and atom-economical means to synthesize α-branched amines. Prior examples featured symmetrical or electronically biased substrates. Here we report a controllable α-functionalization of amines in which regioselectivity can be tuned with minor changes to the reaction conditions.
- Leng, Lingying,Fu, Yue,Liu, Peng,Ready, Joseph M.
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supporting information
p. 11972 - 11977
(2020/08/06)
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- Photocatalyst- And transition-metal-free α-allylation of: N -aryl tetrahydroisoquinolines mediated by visible light
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A convenient and efficient α-allylation of N-aryl tetrahydroisoquinolines has been achieved. This transformation can be realized under only visible light irradiation without the aid of transition metals or photocatalysts. The mechanism involves a novel in situ-generated electron-donor-acceptor (EDA) complex between the N-aryl tetrahydroisoquinolines and an allyl or a benzyl bromide. Irradiation with purple light triggered single-electron transfer (SET) from the N-aryl tetrahydroisoquinolines to the allyl or benzyl bromide of the EDA complex, inducing the formation of the corresponding allyl or benzyl radical and the subsequent radical-radical coupling. This approach represents the first example of a photocatalyst- and transition-metal-free α-allylic and benzylic functionalization of N-aryl tetrahydroisoquinolines.
- Li, Zhuohua,Ma, Pengju,Tan, Yongzhu,Liu, Yufei,Gao, Min,Zhang, Yujun,Yang, Bo,Huang, Xuan,Gao, Yuan,Zhang, Junmin
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supporting information
p. 646 - 650
(2020/02/21)
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- Method for synthesizing tertiary amine derivative by catalyzing hydroboration reaction of tertiary amide by rare earth
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The invention discloses a method for synthesizing a tertiary amine derivative by catalyzing a hydroboration reaction of tertiary amide by rare earth. Under the protection of nitrogen, in a rare earthcatalysis system, the tertiary amine derivative is prepared through a hydrogen transfer reduction reaction catalyzed by rare earth with tertiary amide and pinacol borane as raw materials. The method has the advantages and effects that a novel synthesis process is utilized, and the tertiary amine derivative prepared by using the method disclosed by the invention is high in quality and stable in process; the raw materials are widely sourced or easy to prepare and store, and the reaction yield is high; and in addition, a catalyst can be directly commercially purchased or is easily, directly and simply synthesized, and can be used in actual production.
- -
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Paragraph 0024
(2020/02/27)
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- Redox-Selective Iron Catalysis for α-Amino C-H Bond Functionalization via Aerobic Oxidation
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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
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supporting information
p. 16 - 21
(2019/11/11)
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- Direct benzylation of amines with benzylic alcohols catalyzed by palladium/phosphine-borane catalyst system
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Direct catalytic benzylation of amines with benzylic alcohols to give benzylamines has been newly developed by using palladium/phosphine-borane catalyst system. In this catalytic reaction, the linking between both phosphine and borane moieties in the ligand is very important. Hydroxy group of benzylic alcohols is activated by Lewis acidic borane to form a benzylpalladium intermediate which is attacked by amines to give benzylamine products.
- Onodera, Gen,Kumagae, Hidenobu,Nakamura, Daiki,Hayasaki, Takuto,Fukuda, Tsutomu,Kimura, Masanari
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supporting information
(2020/11/04)
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- Pyrazolyl bistriazolyl phosphine compound and application of pyrazolyl bistriazolyl phosphine compound
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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.
- -
-
Paragraph 0229-0232
(2020/07/24)
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- Preparation method of pyrazole bistriazolylphosphine compound
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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.
- -
-
Paragraph 0227-0230
(2020/05/30)
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- Photo-induced dealdehyding method
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The invention provides a photo-induced dealdehyding method, and belongs to the technical field of organic synthesis. The photo-induced dealdehyding method comprises the following steps that a mixtureof a compound shown in the formula I and a solvent are reacted under an inert gas atmosphere and visible light irradiation, a dealdehyding product is obtained, and no photocatalyst is used in the whole process; wherein the structural formula of the formula I shown in the specification, R is a functional group and is selected from hydrogen, methyl, methoxyl, cyano, chlorine, bromine or fluorine. According to the photo-induced dealdehyding method, in the inert gas atmosphere, the compound shown in the formula (I) can be excited to generate carbon-oxygen bond homogeneous cracking through visiblelight irradiation, then free radical migration and double bond displacement are conducted, finally carbon monoxide is removed, aldehyde group removal is completed, no photocatalyst is needed in the whole process, operation is easy and convenient, and conditions are mild.
- -
-
Paragraph 0048-0053; 0150-0155
(2020/06/16)
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- Direct N-Alkylation/Fluoroalkylation of Amines Using Carboxylic Acids via Transition-Metal-Free Catalysis
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A scalable protocol of direct N-mono/di-alkyl/fluoroalkylation of primary/secondary amines has been constructed with various carboxylic acids as coupling agents under the catalysis of a simple air-tolerant inorganic salt, K3PO4. Advantageous features include 100 examples, 10 drugs and drug-like amines, fluorinated complex tertiary amines, gram-scale synthesis and isotope-labelling amine, thus demonstrating the potential applicability in industry of this methodology. The involvement of relatively less reactive silicon-hydride compared with the traditional reactive metal-hydride or boron-hydride species required to reduce the amide intermediates presumably contributes to the remarkable functional group compatibility. (Figure presented.).
- Lu, Chunlei,Qiu, Zetian,Xuan, Maojie,Huang, Yan,Lou, Yongjia,Zhu, Yiling,Shen, Hao,Lin, Bo-Lin
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supporting information
p. 4151 - 4158
(2020/08/21)
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- Catalyst-free photodecarbonylation ofortho-amino benzaldehyde
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It is almost a consensus that decarbonylation of the aldehyde group (-CHO) needs to not only be mediated by transition metal catalysts, but also requires severe reaction conditions (high temperature and long reaction time). In this work, inspired by the “conformational-selectivity-based” design strategy, we broke this consensus and discovered a catalyst-free photodecarbonylation of the aldehyde group. It revealed that decarbonylation can be easily achieved with visible light irradiation by introducing a tertiary amine into theortho-position of the aldehyde group. A diverse array of tertiary amines is tolerated by our photodecarbonylation under mild conditions. Furthermore, the (QM) computations of the mechanism and the experiments on well-designed special substrates revealed that our photodecarbonylation depends on the conformational specificity of the aldehyde group and tertiary amine, and occurs through an unusual [1,4]-H shift and a subsequent [1,3]-H shift.
- Li, Lamei,Wang, Songping,Wei, Wentao,Yan, Ming,Zhou, Jingwei
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p. 3421 - 3426
(2020/06/25)
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- Homoleptic Bis(trimethylsilyl)amides of Yttrium Complexes Catalyzed Hydroboration Reduction of Amides to Amines
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Homoleptic lanthanide complex Y[N(TMS)2]3 is an efficient homogeneous catalyst for the hydroboration reduction of secondary amides and tertiary amides to corresponding amines. A series of amides containing different functional groups such as cyano, nitro, and vinyl groups were found to be well-tolerated. This transformation has also been nicely applied to the synthesis of indoles and piribedil. Detailed isotopic labeling experiments, control experiments, and kinetic studies provided cumulative evidence to elucidate the reaction mechanism.
- Ye, Pengqing,Shao, Yinlin,Ye, Xuanzeng,Zhang, Fangjun,Li, Renhao,Sun, Jiani,Xu, Beihang,Chen, Jiuxi
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supporting information
p. 1306 - 1310
(2020/02/22)
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- Preparation method of methylamine
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The invention provides a preparation method of methylamine. The preparation method comprises the following step: preparing methylamine by utilizing an amine methylation reaction, wherein in the aminemethylation reaction, the catalyst is dodecyldimethylamine caprolactone. According to the invention, additives required by the reaction are effectively reduced, and the post-treatment process after the reaction is finished is simplified.
- -
-
Paragraph 0047-0053
(2020/12/14)
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- Zn(ii)@TFP-DAQ COF: An efficient mesoporous catalyst for the synthesis of: N -methylated amine and carbamate through chemical fixation of CO2
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Selective N-methylation and carbamate formation reactions were demonstrated via the chemical incorporation of CO2 using a Zn-loaded TFP-DAQ COF (covalent organic framework) as an active catalyst under mild reaction conditions. The selective N-methylation and N-formylation reactions were performed by simply varying the type of solvent. The Zn(ii)@TFP-DAQ COF catalyst was characterized via different characterization techniques such as PXRD, FTIR, UV-vis, N2 adsorption-desorption studies, FESEM and TEM. The catalyst material showed pores in the mesoporous region with a high surface area of 1117.375 m2 g-1. The as-synthesized material was applied as a cheap catalyst for the N-methylation of secondary amines and in carbamate formation reactions with high yields of the desired products up to 98.5% and 97%, respectively, with >99% selectivity. The catalyst was found to be completely heterogeneous and reusable for multiple reaction cycles.
- Sarkar, Priyanka,Chowdhury, Arpita Hazra,Riyajuddin, Sk.,Biswas, Surajit,Ghosh, Kaushik,Islam, Sk. Manirul
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p. 744 - 752
(2020/01/31)
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- Triazinetriamine-derived porous organic polymer-supported copper nanoparticles (Cu-NPs@TzTa-POP): an efficient catalyst for the synthesis of: N -methylated products via CO2fixation and primary carbamates from alcohols and urea
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In recent times, carbon dioxide fixation has received much attention for its potential application as an abundant C1 source and a range of important fine chemicals can be manufactured via this fixation. Here, a copper nanoparticle-decorated porous organic polymer-based (Cu-NPs@TzTa-POP) material was prepared by a simple in situ process. The catalyst was characterized by various techniques such as UV-vis spectra, FTIR spectra, HR-TEM, PXRD, N2 adsorption-desorption, TG-DTA, XPS, and AAS analysis. The synthesized heterogeneous catalyst showed excellent activity in an atmospheric carbon dioxide fixation reaction to produce N-methylated products from aromatic/heterocyclic amines in the presence of polymethyl-hydrosiloxane (PMHS) as the reducing agent at 80 °C within 12 h of the reaction. Through this catalytic N-methylation reaction, we obtained 98% yield of the product with turnover frequency ranging from 18 to 42 h-1. The catalyst is also very stable for the formation of primary carbamates from alcohols using the eco-friendly carbonylating agent, urea. Diverse alcohols (such as benzylic alcohols, phenols, heterocyclic alcohols, as well as aliphatic alcohols) showed much acceptance to this catalytic reaction and produced moderate to excellent yields of the respective carbamate products under ambient reaction conditions. Moreover, Cu-NPs@TzTa-POP is effortlessly recyclable and reusable without the extensive loss of active copper metal centres for many catalytic rounds (up to six catalytic rounds were examined).
- Haque, Najirul,Biswas, Surajit,Basu, Priyanka,Haque Biswas, Imdadul,Khatun, Resmin,Khan, Aslam,Islam, Sk Manirul
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supporting information
p. 15446 - 15458
(2020/10/22)
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- Chiral tetraaryl-and tetraalkynylborates as chiral solvating agents for tetraalkylammonium salts
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The application of tetracarbon-substituted chiral borate sodium salts (NaBR*4) as NMR chiral solvating agents for various tetraalkylammonium salts (R4NX) has been successfully demonstrated. Ion exchange between R4NX and NaBR*4 proceeded in excellent yields and provided the corresponding dia-stereomeric salts (R4NBR*4). The ee values of the R4NX salts were determined by1H NMR analysis of R4NBR*4. Two types of chiral borates, tetraaryl-and tetraalkynylborates with optically active 1,1′-binaphthyl components were used. At the beginning of this research, we investigated the efficacy of a known chiral tetraar-ylborate developed by Pommerening et al. for R4NX. To expand the possibility of further structural design of the chiral borate, we designed chiral tetraalkynylborates as a new structure. Their synthesis and application are also described.
- Tayama, Eiji,Sugawara, Takeshi
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supporting information
p. 803 - 811
(2019/01/18)
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- Electrochemical Regioselective Bromination of Electron-Rich Aromatic Rings Using n Bu 4 NBr
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Electrochemical regioselective bromination of electron-rich aromatic rings using stoichiometric tetrabutylammonium bromide (n Bu 4 NBr) has been accomplished under mild conditions. This protocol provides an environmentally friendly and simple way for the construction of C-Br bond in moderate to high yields with wide functional group tolerance.
- Bai, Ya,Che, Xin,Liu, Nian,Ning, Shulin,Shi, Lingling,Wang, Shutao,Wang, Siyu,Xiang, Jinbao,Xie, Wenxia
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supporting information
p. 1313 - 1316
(2019/06/20)
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- Endergonic addition of N -methylamines to aromatic ketones driven by photochemical offset of the entropic cost
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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
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supporting information
p. 11683 - 11686
(2019/10/02)
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- Nickel-Catalyzed Decarboxylation of Aryl Carbamates for Converting Phenols into Aromatic Amines
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Herein, we describe a new catalytic approach to accessing aromatic amines from an abundant feedstock, namely phenols. The most reliable catalytic method for converting phenols to aromatic amines uses an activating group, such as a trifluoromethane sulfonyl group. However, this activating group is eliminated as a leaving group during the amination process, resulting in significant waste. Our nickel-catalyzed decarboxylation reaction of aryl carbamates forms aromatic amines with carbon dioxide as the only byproduct. As this amination proceeds in the absence of free amines, a range of functionalities, including a formyl group, are compatible. A bisphosphine ligand immobilized on a polystyrene support (PS-DPPBz) is key to the success of this reaction, generating a catalytic species that is significantly more active than simple nonsupported variants.
- Nishizawa, Akihiro,Takahira, Tsuyoshi,Yasui, Kosuke,Fujimoto, Hayato,Iwai, Tomohiro,Sawamura, Masaya,Chatani, Naoto,Tobisu, Mamoru
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supporting information
p. 7261 - 7265
(2019/05/16)
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- Sodium Triethylborohydride-Catalyzed Controlled Reduction of Unactivated Amides to Secondary or Tertiary Amines
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The first transition-metal-free catalytic protocol for controlled reduction of amide functions using cheap and bench-stable hydrosilanes as reducing agents has been established. By altering the hydrosilane and solvent, the new method enables the selective cleavage of unactivated C-O bonds in amides and allows the C-N bonds to selectively break via the deacylated cleavage. Overall, this novel process may offer a versatile alternative to current methodologies employing stoichiometric metal systems for the controlled reduction of carboxamides.
- Yao, Wubing,He, Lili,Han, Deman,Zhong, Aiguo
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- Sodium Triethylborohydride-Catalyzed Controlled Reduction of Unactivated Amides to Secondary or Tertiary Amines
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The first transition-metal-free catalytic protocol for controlled reduction of amide functions using cheap and bench-stable hydrosilanes as reducing agents has been established. By altering the hydrosilane and solvent, the new method enables the selective cleavage of unactivated C-O bonds in amides and allows the C-N bonds to selectively break via the deacylated cleavage. Overall, this novel process may offer a versatile alternative to current methodologies employing stoichiometric metal systems for the controlled reduction of carboxamides.
- Yao, Wubing,He, Lili,Han, Deman,Zhong, Aiguo
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p. 14627 - 14635
(2019/12/02)
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- Ru-Catalyzed Deoxygenative Transfer Hydrogenation of Amides to Amines with Formic Acid/Triethylamine
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A ruthenium(II)-catalyzed deoxygenative transfer hydrogenation of amides to amines using HCO2H/NEt3 as the reducing agent is reported for the first time. The catalyst system consisting of [Ru(2-methylallyl)2(COD)], 1,1,1-tris(diphenylphosphinomethyl) ethane (triphos) and Bis(trifluoromethane sulfonimide) (HNTf2) performed well for deoxygenative reduction of various secondary and tertiary amides into the corresponding amines in high yields with excellent selectivities, and exhibits high tolerance toward functional groups including those that are reduction-sensitive. The choice of hydrogen source and acid co-catalyst is critical for catalysis. Mechanistic studies suggest that the reductive amination of the in situ generated alcohol and amine via borrowing hydrogen is the dominant pathway. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Xu, Xin,Zhao, Haoqiang,Han, Jiahong,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 3800 - 3806
(2019/07/12)
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- B(C6F5)3-Catalyzed Deoxygenative Reduction of Amides to Amines with Ammonia Borane
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The first B(C6F5)3-catalyzed deoxygenative reduction of amides into the corresponding amines with readily accessible and stable ammonia borane (AB) as a reducing agent under mild reaction conditions is reported. This metal-free protocol provides facile access to a wide range of structurally diverse amine products in good to excellent yields, and various functional groups including those that are reduction-sensitive were well tolerated. This new method is also applicable to chiral amide substrates without erosion of the enantiomeric purity. The role of BF3 ? OEt2 co-catalyst in this reaction is to activate the amide carbonyl group via the in situ formation of an amide-boron adduct. (Figure presented.).
- Pan, Yixiao,Luo, Zhenli,Han, Jiahong,Xu, Xin,Chen, Changjun,Zhao, Haoqiang,Xu, Lijin,Fan, Qinghua,Xiao, Jianliang
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supporting information
p. 2301 - 2308
(2019/01/30)
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- Method for selective reducing reaction of tertiary aryl amide and borane
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The present invention relates to a method for a selective reducing reaction of a tertiary aryl amide and borane. A tertiary amine product is prepared by the reducing reaction of a tertiary aryl amidederivative and a cheap and easily available organoboron reagent under mild conditions under the convenient catalysis of a non-transition metal compound sodium triethylborohydride used as a catalyst for the first time. Compared with traditional methods, the method of the method generally has the advantages of wide universality of a substrate, low cost and easy availability of the catalyst, and simplicity in reaction operation. The selective reducing reaction of the tertiary aryl amide compound and the organoboron reagent under the catalysis of the transition metal catalyst is realized for the first time, and a brand new "green" reaction strategy is provided for the laboratory preparation or industrial production of tertiary arylamine products.
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Paragraph 0069-0072
(2019/10/23)
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- Phosphine-Free Well-Defined Mn(I) Complex-Catalyzed Synthesis of Amine, Imine, and 2,3-Dihydro-1 H-perimidine via Hydrogen Autotransfer or Acceptorless Dehydrogenative Coupling of Amine and Alcohol
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The application of nontoxic, earth-abundant transition metals in place of costly noble metals is a paramount goal in catalysis and is especially interesting if the air- and moisture-stable ligand scaffold is used. Herein, we report the synthesis of amines/imines directly from alcohol and amines via hydrogen autotransfer or acceptorless dehydrogenation catalyzed by well-defined phosphine-free Mn complexes. Both imines and amines can be obtained from the same set of alcohols and amines using the same catalyst, only by tuning the reaction conditions. The amount and nature of the base are found to be a highly important aspect for the observed selectivity. Both the primary and secondary amines have been employed as substrates for the N-alkylation reaction. As a highlight, we showed the chemoselective synthesis of resveratrol derivatives. Furthermore, the Mn-catalyzed dehydrogenative synthesis of structurally important 2,3-dihydro-1H-perimidines has also been demonstrated. Density functional theory calculations were also carried out to model the reaction path and to calculate the reaction profile.
- Das, Kalicharan,Mondal, Avijit,Pal, Debjyoti,Srivastava, Hemant Kumar,Srimani, Dipankar
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supporting information
p. 1815 - 1825
(2019/04/30)
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- Robust Buchwald-Hartwig amination enabled by ball-milling
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An operationally simple mechanochemical method for the Pd catalysed Buchwald-Hartwig amination of arylhalides with secondary amines has been developed using a Pd PEPPSI catalyst system. The system is demonstrated on 30 substrates and applied in the context of a target synthesis. Furthermore, the performance of the reaction under aerobic conditions has been probed under traditional solution and mechanochemical conditions, the observations are discussed herein.
- Cao, Qun,Nicholson, William I.,Jones, Andrew C.,Browne, Duncan L.
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supporting information
p. 1722 - 1726
(2019/02/20)
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- Air-tolerant direct reductive N-methylation of amines using formic acid via simple inorganic base catalysis
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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
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supporting information
(2019/05/29)
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- UiO-type metal-organic frameworks with NHC or metal-NHC functionalities for: N-methylation using CO2 as the carbon source
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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
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supporting information
p. 11928 - 11931
(2019/10/11)
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- Mn-Catalyzed Selective Double and Mono-N-Formylation and N-Methylation of Amines by using CO2
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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
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p. 3054 - 3059
(2019/04/10)
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- Eco-friendly acetylcholine-carboxylate bio-ionic liquids for controllable: N-methylation and N-formylation using ambient CO2 at low temperatures
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Catalytic fixation of CO2 to produce valuable fine chemicals is of great significance to develop a green and sustainable circulation of excessive carbon in the environment. Herein, a series of non-toxic, biodegradable and recyclable acetylcholine-carboxylate bio-ionic liquids with different cations and anions were simply synthesized for producing formamides and methylamines using atmospheric CO2 as a carbon source, and phenylsilane as a hydrogen donor. The selectivity toward products was tuned by altering the reaction temperature under solvent or solvent-free conditions. N-Methylamines (ca. 96% yield) were obtained in acetonitrile at 50 °C, while N-formamides (ca. 99% yield) were attained without a solvent at 30 °C. The established bio-ionic liquid catalytic system found a wide range of applicability in substrates and possessed a high potentiality in scale-up to gram-grade production. The developed catalytic system was fairly stable, which could be easily reused without an apparent loss of reactivity, possibly due to the strong electrostatic interactions between the cation and anion. The combination of experimental and computational results explicitly elucidated the reaction mechanism: PhSiH3 activated by a bio-IL was favorable for the formation of silyl formate from hydrosilylation of CO2, followed by a reaction with an amine to give an N-formamide, while an N-methylamine was formed by further hydrosilylation of the N-formamide.
- Zhao, Wenfeng,Chi, Xiaoping,Li, Hu,He, Jian,Long, Jingxuan,Xu, Yufei,Yang, Song
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supporting information
p. 567 - 577
(2019/02/14)
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- 2-Aminoquinazolin-4(3H)-one as an Organocatalyst for the Synthesis of Tertiary Amines
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The potential of 2-aminoquinazolin-4(3H)-one as an organocatalyst for the activation of aldehydes via noncovalent interaction for the synthesis of tertiary amines using formic acid as a reducing agent is reported for the first time. The developed protocol demonstrated a dilated substrate scope for aromatic and aliphatic amines with aromatic and aliphatic aldehydes. Furthermore, the current method was also fruitful for the derivatization of ciprofloxacin and its derivative in good to excellent yields.
- Thakur, Maheshwar S.,Nayal, Onkar S.,Upadhyay, Rahul,Kumar, Neeraj,Maurya, Sushil K.
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supporting information
p. 1359 - 1362
(2018/03/09)
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