- The scale-up of continuous biphasic liquid/liquid reactions under super-heating conditions: Methodology and reactor design
-
Biphasic liquid/liquid reactions are commonplace, however their scale-up under super-heating conditions is not. Even more challenging efforts have to be expected in the case of a large scale continuous production process, which also includes the development at a lab scale, the selection and design of the continuous reaction equipment. However, by running chemistry above the boiling point of the solvent, the solvent selection can be widened to include green solvents and continuous processing guarantees a limited and safe footprint. Herein is reported a systematic methodology for the development and scale-up of a biphasic reaction under super-heating conditions, as well as the design of a continuous reactor column suitable for handling such conditions. Taking the alkylation of benzylamine with 1,5-dibromopentane as a model reaction, kinetic determination and fluid dynamic characterization of the biphasic media have been instrumental for a successful scale-up concept which was proven in a custom-made hastelloy reactor column.
- Mandrelli, Francesca,Buco, Alessia,Piccioni, Lorenzo,Renner, Florian,Guelat, Bertrand,Martin, Benjamin,Schenkel, Berthold,Venturoni, Francesco
-
-
Read Online
- NUCLEOPHILIC DISPLACEMENT OF N-BENZYL GROUPS: EFFECT OF PYRIDINIUM ON RATES AND MECHANISM
-
Steric acceleration by α-substituents in pyridine leaving groups is quantitatively assessed.Constraint of α-phenyls to near planarity forms superior leaving groups for SN2 displacements. α-t-Butyl groups significantly increase SN1 dissociation.
- Katritzky, Alan R.,Musumarra, Giuseppe,Sakizadeh, Kumars
-
-
Read Online
- Deoxygenative hydroboration of primary, secondary, and tertiary amides: Catalyst-free synthesis of various substituted amines
-
Transformation of relatively less reactive functional groups under catalyst-free conditions is an interesting aspect and requires a typical protocol. Herein, we report the synthesis of various primary, secondary, and tertiary amines through hydroboration of amides using pinacolborane under catalyst-free and solvent-free conditions. The deoxygenative hydroboration of primary and secondary amides proceeded with excellent conversions. The comparatively less reactive tertiary amides were also converted to the corresponding N,N-diamines in moderate yields under catalyst-free conditions, although alcohols were obtained as a minor product.
- An, Duk Keun,Jaladi, Ashok Kumar,Kim, Hyun Tae,Yi, Jaeeun
-
-
- Method for catalyzing hydrodesulfurization of thioamide derivative
-
The invention provides a method for catalyzing hydrodesulfurization of a thioamide derivative, which comprises the following steps: sequentially adding a pentacarbonyl manganese bromide catalyst, a reaction substrate thioamide derivative, Lewis acid, a solvent and alkali into a polytetrafluoroethylene lined reaction tube, putting the reaction tube into a high-pressure kettle, introducing hydrogen to carry out catalytic hydrogenation reaction, cooling to room temperature, discharging gas, washing the reaction tube with ethyl acetate, passing through a silica gel small short column, carrying out spin drying, and carrying out column chromatography purification to obtain a target product. The monovalent manganese which is low in toxicity and good in chemical selectivity and biocompatibility is used as the catalyst to catalyze hydrodesulfurization of the thioamide derivative, the substrate range is wide, the yield of amine is high, and the method has high drug synthesis application value.
- -
-
Paragraph 0019-0023
(2021/07/09)
-
- Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
-
Here we describe the discovery of a new class of C-H borylation catalysts and their use for regioselective C-H borylation of aromatic, heteroaromatic, and aliphatic systems. The new catalysts have Ir-C(thienyl) or Ir-C(furyl) anionic ligands instead of the diamine-type neutral chelating ligands used in the standard C-H borylation conditions. It is reported that the employment of these newly discovered catalysts show excellent reactivity and ortho-selectivity for diverse classes of aromatic substrates with high isolated yields. Moreover, the catalysts proved to be efficient for a wide number of aliphatic substrates for selective C(sp3)-H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C-H bonds. A number of late-stage C-H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)-H and C(sp3)-H borylations enabling the method more general. Preliminary mechanistic studies suggest that the active catalytic intermediate is the Ir(bis)boryl complex, and the attached ligand acts as bidentate ligand. Collectively, this study underlines the discovery of new class of C-H borylation catalysts that should find wide application in the context of C-H functionalization chemistry.
- Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
-
supporting information
p. 5022 - 5037
(2021/05/04)
-
- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
-
A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
- Bera, Jitendra K.,Pandey, Pragati
-
supporting information
p. 9204 - 9207
(2021/09/20)
-
- Hydrosilane-Mediated Electrochemical Reduction of Amides
-
Electrochemical reduction of amides was achieved by using a hydrosilane without any toxic or expensive metals. The key reactive ketyl radical intermediate was generated by cathodic reduction. Continuous reaction with anodically generated silyl radicals or zinc bromide resulted in chemoselective deoxygenation to give the corresponding amines.
- Okamoto, Kazuhiro,Nagahara, Shingo,Imada, Yasushi,Narita, Risako,Kitano, Yoshikazu,Chiba, Kazuhiro
-
p. 15992 - 16000
(2021/07/20)
-
- Zirconium-hydride-catalyzed site-selective hydroboration of amides for the synthesis of amines: Mechanism, scope, and application
-
Developing mild and efficient catalytic methods for the selective synthesis of amines is a longstanding research objective. In this respect, catalytic deoxygenative amide reduction has proven to be promising but challenging, as this approach necessitates selective C–O bond cleavage. Herein, we report the selective hydroboration of primary, secondary, and tertiary amides at room temperature catalyzed by an earth-abundant-metal catalyst, Zr-H, for accessing diverse amines. Various readily reducible functional groups, such as esters, alkynes, and alkenes, were well tolerated. Furthermore, the methodology was extended to the synthesis of bio- and drug-derived amines. Detailed mechanistic studies revealed a reaction pathway entailing aldehyde and amido complex formation via an unusual C–N bond cleavage-reformation process, followed by C–O bond cleavage.
- Han, Bo,Jiao, Haijun,Wu, Lipeng,Zhang, Jiong
-
p. 2059 - 2067
(2021/09/02)
-
- Lithium compound catalyzed deoxygenative hydroboration of primary, secondary and tertiary amides
-
A selective and efficient route for the deoxygenative reduction of primary to tertiary amides to corresponding amines has been achieved with pinacolborane (HBpin) using simple and readily accessible 2,6-di-tert-butyl phenolate lithium·THF (1a) as a catalyst. Both experimental and DFT studies provide mechanistic insight. This journal is
- Bisai, Milan Kumar,Gour, Kritika,Das, Tamal,Vanka, Kumar,Sen, Sakya S.
-
supporting information
p. 2354 - 2358
(2021/03/03)
-
- Manganese-Catalyzed Hydroborations with Broad Scope
-
Reductive transformations of easily available oxidized matter are at the heart of synthetic manipulation and chemical valorization. The applications of catalytic hydrofunctionalization benefit from the use of liquid reducing agents and operationally facile setups. Metal-catalyzed hydroborations provide a highly prolific platform for reductive valorizations of stable C=X electrophiles. Here, we report an especially facile, broad-scope reduction of various functions including carbonyls, carboxylates, pyridines, carbodiimides, and carbonates under very mild conditions with the inexpensive pre-catalyst Mn(hmds)2. The reaction could be successfully applied to depolymerizations.
- Ghosh, Pradip,Jacobi von Wangelin, Axel
-
supporting information
p. 16035 - 16043
(2021/06/16)
-
- Direct: N -alkylation of sulfur-containing amines
-
An efficient ruthenium-catalyzed method has been developed for the direct N-alkylation of sulfur-containing amines with alcohols, for the first time, by a step-economical and environmentally friendly hydrogen borrowing strategy. The present methodology features base-free conditions and broad substrate scope, with water being the only by-product. Moreover, this protocol has been applied to the synthesis of the pharmaceutical drug Quetiapine.
- Li, Chen,Ge, Min-Tong,Bai, Liang,Xia, Ai-Bao,Xu, Dan-Qian,Xu, Zhen-Yuan
-
supporting information
p. 4478 - 4482
(2021/05/31)
-
- Iridium and bis(4-nitrophenyl)phosphoric acid catalysed amination of diol by hydrogen-borrowing methodology for the synthesis of cyclic amine: Synthesis of clopidogrel
-
The borrowing hydrogen method is an environmentally benign process for the synthesis of amines, as H2O is the side product. A new green process for the amination of diol by [Ir] catalyst 15 and bis(4-nitrophenyl)phosphoric acid for the synthesis of cyclic amine is reported. This method was successfully applied for the synthesis of antiplatelet drug clopidogrel.
- Swain, Sharada Prasanna,Shri, Om,Ravichandiran
-
-
- BF3·Et2O as a metal-free catalyst for direct reductive amination of aldehydes with amines using formic acid as a reductant
-
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
-
supporting information
p. 5205 - 5211
(2021/07/29)
-
- Trimethyl Borate-Catalyzed, Solvent-Free Reductive Amination
-
Solvent-free reductive amination of aldehydes and ketones with aliphatic and aromatic amines in high-to-excellent yields has been achieved with sub-stoichiometric trimethyl borate as promoter and ammonia borane as reductant.
- Ramachandran, P. Veeraraghavan,Choudhary, Shivani,Singh, Aman
-
p. 4274 - 4280
(2021/03/09)
-
- Iodine-Mediated Coupling of Cyclic Amines with Sulfonyl Hydrazides: an Efficient Synthesis of Vinyl Sulfone Derivatives
-
An efficient iodine-mediated coupling of cyclic amines with sulfonyl hydrazides is reported. This transformation opens a new route to the synthesis of vinyl sulfones derivatives, which is a common structural motif in natural products and pharmaceuticals. Tentative mechanistic studies suggest that this reaction is likely to involve a radical process.
- Rong, Xiaona,Guo, Jingwen,Hu, Zheqi,Huang, Lehao,Gu, Yugui,Cai, Yuepiao,Liang, Guang,Xia, Qinqin
-
supporting information
p. 701 - 708
(2020/12/30)
-
- Efficient One-Pot Reductive Aminations of Carbonyl Compounds with Aquivion-Fe as a Recyclable Catalyst and Sodium Borohydride
-
A one-pot reductive amination of aldehydes and ketones with NaBH4 was developed with a view to providing efficient, economical and greener synthetic conditions. A recyclable iron-based Lewis catalyst, Aquivion-Fe, was used to promote imine formation in cyclopentyl methyl ether, followed by the addition of a small amount of methanol to the reaction mixture to enable C=N reduction by NaBH4. The protocol, applied to a wide number of amines and carbonyl compounds, resulted in ever complete conversion of these latter with excellent chemoselectivity towards the expected amination products in the most cases. Isolated yields, determined for a selection of the screened substrates, were found consistent with the previously obtained conversion and selectivity data. Cinacalcet, an important active pharmaceutical ingredient, was efficiently prepared by the title procedure.
- Airoldi, Veronica,Piccolo, Oreste,Roda, Gabriella,Appiani, Rebecca,Bavo, Francesco,Tassini, Riccardo,Paganelli, Stefano,Arnoldi, Sebastiano,Pallavicini, Marco,Bolchi, Cristiano
-
supporting information
p. 162 - 168
(2019/12/11)
-
- Synthesis of Biaryls Having a Piperidylmethyl Group Based on Space Integration of Lithiation, Borylation, and Suzuki–Miyaura Coupling
-
In a flow microreactor, aryllithiums bearing a piperidylmethyl group were generated using nBuLi by precise residence time control and effective temperature control, and then selectively borylated with boronic esters such as 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (BpinOiPr) and trimethyl borate B(OMe)3 by fast mixing. Moreover, the direct integration with Suzuki–Miyaura cross coupling were successfully achieved to obtain nitrogen-containing biaryl compounds. The present method could be applied for the straightforward synthesis of the key intermediate of a bioactive component bearing a piperidylmethyl-biphenyl framework.
- Aizawa, Yoko,Ashikari, Yosuke,Colella, Marco,Fujita, Chiemi,Higuma, Ryosuke,Ishikawa, Susumu,Jiang, Yiyuan,Luisi, Renzo,Maekawa, Kei,Nagaki, Aiichiro,Sakaue, Hodaka,Shimizu, Yutaka,Shite, Ibuki,Takahashi, Yusuke,Takegawa, Toshihiro,Takumi, Masahiro,Yamashita, Hiroki,Yonekura, Yuya
-
p. 618 - 622
(2020/02/04)
-
- Selective 1,2-Aryl-Aminoalkylation of Alkenes Enabled by Metallaphotoredox Catalysis
-
A highly chemo- and regioselective intermolecular 1,2-aryl-aminoalkylation of alkenes by photoredox/nickel dual catalysis is described here. This three-component conjunctive cross-coupling is highlighted by its first application of primary alkyl radicals, which were not compatible in previous reports. The readily prepared α-silyl amines could be transferred to α-amino radicals by photo-induced single electron transfer step. The radical addition/cross-coupling cascade reaction proceeds under mild, base-free and redox-neutral conditions with good functional group tolerance, and importantly, provides an efficient and concise method for the synthesis of structurally valuable α-aryl substituted γ-amino acid derivatives motifs.
- Chen, Zimin,Hu, Yuanyuan,Li, Weirong,Liao, Zixuan,Xi, Xiaoxiang,Yuan, Weiming,Zheng, Songlin
-
p. 17910 - 17916
(2020/08/21)
-
- La[N(sime3)2]3-catalyzed deoxygenative reduction of amides with pinacolborane. scope and mechanism
-
Tris[N,N-bis(trimethylsilyl)amide]lanthanum (LaNTMS) is an efficient and selective homogeneous catalyst for the deoxygenative reduction of tertiary and secondary amides with pinacolborane (HBpin) at mild temperatures (25-60 °C). The reaction, which yields amines and O(Bpin)2, tolerates nitro, halide, and amino functional groups well, and this amide reduction is completely selective, with the exclusion of both competing inter- and intramolecular alkene/alkyne hydroboration. Kinetic studies indicate that amide reduction obeys an unusual mixed-order rate law which is proposed to originate from saturation of the catalyst complex with HBpin. Kinetic and thermodynamic studies, isotopic labeling, and DFT calculations using energetic span analysis suggest the role of a [(Me3Si)2N]2La-OCHR(NR′2)[HBpin] active catalyst, and hydride transfer is proposed to be ligand-centered. These results add to the growing list of transformations that commercially available LaNTMS is competent to catalyze, further underscoring the value and versatility of lanthanide complexes in homogeneous catalysis.
- Barger, Christopher J.,Dicken, Rachel D.,Weidner, Victoria L.,Motta, Alessandro,Lohr, Tracy L.,Marks, Tobin J.
-
supporting information
p. 8019 - 8028
(2020/05/27)
-
- Method for catalytically synthesizing 1-substituted pyrrolidine/piperidine derivative by using supported metal
-
The invention provides a method for catalytically synthesizing a 1-substituted pyrrolidine/piperidine derivative by using a supported metal. The method comprises: carrying out a reaction with ammoniato form a pyrrolidine ring/piperidine ring by using a supported metal as a catalyst, using 1,4-butanediol/1, 5-pentanediol as a cyclization raw material and using alcohol as an N-alkylation raw material, wherein the high-selectivity synthesis of the 1-substituted pyrrolidine/piperidine derivative is achieved through the one-step reaction, the active components of the supported metal catalyst are Cu, Ni and Pd/Ru, the total loading capacity of the active components Cu and Ni is 3-15 wt% of the carrier, and the loading capacity of Pd/Ru is 0-1 wt% of the carrier. According to the invention, themethod is simple, low in cost and environmentally friendly, the conversion rate of 1,4-butanediol/1,5-pentanediol is high, the selectivity of the pyrrolidine/piperidine derivatives is high, and the method is a production route with practical application value.
- -
-
Paragraph 0027
(2020/02/20)
-
- Scalable preparation of stable and reusable silica supported palladium nanoparticles as catalysts for N-alkylation of amines with alcohols
-
The development of nanoparticles-based heterogeneous catalysts continues to be of scientific and industrial interest for the advancement of sustainable chemical processes. Notably, up-scaling the production of catalysts to sustain unique structural features, activities and selectivities is highly important and remains challenging. Herein, we report the expedient synthesis of Pd-nanoparticles as amination catalysts by the reduction of simple palladium salt on commercial silica using molecular hydrogen. The resulting Pd-nanoparticles constitute stable and reusable catalysts for the synthesis of various N-alkyl amines using borrowing hydrogen technology without the use of any base or additive. By applying this Pd-based catalyst, functionalized and structurally diverse N-alkylated amines as well as some selected drug molecules were synthesized in good to excellent yields. Practical and synthetic utility of this Pd-based amination protocol has been demonstrated by upscaling catalyst preparation and amination reactions to several grams-scales as well as recycling of catalyst. Noteworthy, this Pd-catalyst preparation has been up-scaled to kilogram scale and catalysts prepared in both small (1 g) and large-scale (kg) exhibited similar structural features and activity.
- Alshammari, Ahmad S.,Natte, Kishore,Kalevaru, Narayana V.,Bagabas, Abdulaziz,Jagadeesh, Rajenahally V.
-
p. 141 - 149
(2020/01/06)
-
- Iridium complexes with a new type of N^N′-donor anionic ligand catalyze the N-benzylation of amines via borrowing hydrogen
-
The development of efficient and eco-friendly methods for the synthesis of elaborate amines is highly desired as they are valuable chemicals. The catalytic alkylation of amines using alcohols as alkylating agents, through the so-called borrowing hydrogen process, satisfies several of the principles of green chemistry. In this paper, four neutral half-sandwich complexes of Ru(II), Rh(III), and Ir(III) have been synthesized and tested as catalysts in the N-benzylation of amines with benzyl alcohol. The new derivatives contain a N^N′ anionic ligand derived from 5-(pyridin-2-ylmethylene)hydantoin (Hpyhy) that has never been tested in metal complexes with catalytic applications. In particular, the Ir derivatives, [(Cp*)IrX(pyhy)] (X = Cl or H), exhibit high activity along with good selectivity in the process. Indeed, the scope of the optimized protocol has been proved in the benzylation of several primary and secondary amines. The selectivity towards monoalkylated or dialkylated amines has been tuned by adjusting the amine:alcohol ratio and the reaction time. Experimental results support a mechanism consisting of three consecutive steps, two of which are Ir catalyzed, and a favorable condensation step without the assistance of the catalyst. Moreover, an unproductive competitive pathway can operate when the reaction is performed in open-air vessels, due to the irreversible release of H2. This route is hampered when the reaction is carried out in close vessels, likely because the release of H2 is reversed through metal-based heterolytic cleavage. From our viewpoint, these results show the potential of the new catalysts in a very attractive and promising methodology for the synthesis of amines.
- Ruiz-Casta?eda, Margarita,Rodríguez, Ana M.,Aboo, Ahmed H.,Manzano, Blanca R.,Espino, Gustavo,Xiao, Jianliang,Jalón, Félix A.
-
-
- High-Throughput Screening of Reductive Amination Reactions Using Desorption Electrospray Ionization Mass Spectrometry
-
This study describes the latest generation of a high-throughput screening system that is capable of screening thousands of organic reactions in a single day. This system combines a liquid handling robot with desorption electrospray ionization (DESI) mass spectrometry (MS) for a rapid reaction mixture preparation, accelerated synthesis, and automated MS analysis. A total of 3840 unique reductive amination reactions were screened to demonstrate the throughputs that are capable with the system. Products, byproducts, and intermediates were all monitored in full-scan mass spectra, generating a complete view of the reaction progress. Tandem mass spectrometry experiments were conducted to verify the identity of the products formed. The amine and electrophile reactivity trends represented in the data match what is expected from theory, indicating that the system accurately models the reaction performance. The DESI results correlated well with those generated using more traditional mass spectrometry techniques like liquid chromatography-mass spectrometry, validating the data generated by the system.
- Cooks, R. Graham,Ferreira, Christina R.,Li, Yangjie,Logsdon, David L.,Paschoal Sobreira, Tiago Jose,Thompson, David H.
-
supporting information
p. 1647 - 1657
(2020/10/26)
-
- Hydrazone complexes of ruthenium(II): Synthesis, crystal structures and catalytic applications in N-alkylation reactions
-
A series of new Ru(II) complexes of 8-hydroxy quinoline-2-carboxyaldehyde hydrazone of the general formula [RuH(CO)(EPh3)2L] (1–6) (E = P or As, L = N’-((8-hydroxyquinolin-2-yl)methylene)thiophene-2-carbohydrazide (HQ-THy), N’-((8-hydroxyquinolin-2-yl)methylene)isonicotinohydrazide (HQ-IHy), N’-((8-hydroxyquinolin-2-yl)methylene) benzohydrazide (HQ-BHy)) have been synthesized. They have been characterized by elemental analysis, IR, NMR (1H, 13C & 31P) and ESI-MS spectral methods. Further, structures of two of the complexes have been determined by single crystal X-ray diffraction technique which revealed a pseudo octahedral geometry with the coordination of the quinoline nitrogen and quinoline oxygen atoms of the ligand. All the new complexes have been employed as efficient catalysts in N-alkylation reactions for the synthesis of tertiary amines by the coupling of secondary amines with aromatic primary alcohols at low catalyst loading with maximum yields. In addition, the effects of substituents on the ligands, different solvents as well as bases and amounts of catalyst loading on the catalytic activity of the complexes have been thoroughly investigated. Complex 1 was found to be efficient catalyst towards N-alkylation of alcohols with the amine. Further, a variety of secondary amines and aromatic (hetero) primary alcohols with various functional groups have also been successfully used in the N-alkylation reactions and it has been found that only one equivalent of the alcohol was consumed in the process.
- Murugan, Kaliyappan,Natarajan, Karuppannan,Nirmala, Muthukumaran,Vijayapritha, Subbarayan,Viswanathamurthi, Periasamy
-
-
- Iron-Catalysed Reductive Amination of Carbonyl Derivatives with Ω-Amino Fatty Acids to Access Cyclic Amines
-
An efficient method for the reductive amination of carbonyl derivatives with ω-amino fatty acids catalysed by an iron complex Fe(CO)4(IMes) [IMes=1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene] by means of hydrosilylation was developed. A variety of pyrrolidines, piperidines and azepanes were selectively synthesised in moderate-to-excellent yields (36 examples, 47–97 % isolated yield) with a good functional group tolerance.
- Wei, Duo,Netkaew, Chakkrit,Carré, Victor,Darcel, Christophe
-
p. 3008 - 3012
(2019/05/15)
-
- Heterogeneous Catalytic Reduction of Tertiary Amides with Hydrosilanes Using Unsupported Nanoporous Gold Catalyst
-
We have demonstrated that the unsupported nanoporous gold (AuNPore) was a green and highly efficient heterogeneous catalyst for the reduction of amides to amines using hydrosilanes as reductants. A variety of tertiary amides with a broad functional groups were reduced to the corresponding tertiary amines in the presence of 2 mol% of AuNPore and PheMe2SiH or (Me2SiH)2O under mild conditions. AuNPore catalyst was recovered by simple filtration and used for twelve times without any loss of catalytic activity. The AuNPore/hydrosilane system was also successfully applied to the hydrosilative reduction of sulfoxides and N-oxides. (Figure presented.).
- Zhao, Yuhui,Zhang, Sheng,Yamamoto, Yoshinori,Bao, Ming,Jin, Tienan,Terada, Masahiro
-
supporting information
p. 4817 - 4824
(2019/10/28)
-
- Hydrosilylative Reduction of Tertiary Amides to Amines Catalyzed by N-(Phosphinoaryl)anilido Complexes of Iron and Cobalt
-
The synthesis and structural characterization of low-coordinate Fe(II) and Co(II) complexes supported by the monoanionic P,N-ligand N-(2-dicyclohexylphosphinophenyl)-2,6-diisopropylanilide are described. A three-coordinate (P,N)Fe-hexamethyldisilazide complex (2), and four-coordinate (P,N)Fe- (3-Fe) and (P,N)Co-alkyl (3-Co) complexes were evaluated as pre-catalysts for the hydrosilylative reduction of amides with PhSiH3 (5 mol % pre-catalyst, 1 equiv. PhSiH3, 80 °C, 1–24 h). The Fe complex 2 proved to be more broadly effective for the reduction of a variety of tertiary amide substrates, and was shown to mediate the reduction of N,N-dibenzylbenzamide at a loading of 1 mol %, to achieve near quantitative formation of tribenzylamine in 1 h (80 °C). Complex 2 also proved effective for the hydrosilylation of tertiary amides under ambient conditions (5 mol % Fe, 24 h), which is a unique example of room temperature amide hydrosilylation mediated by an Fe catalyst without the need for photochemical activation. Given the widespread use of amide reduction protocols in synthesis, the development of efficient Fe-based catalysts that operate under mild conditions is an important target.
- Hale, Dylan J.,Murphy, Luke J.,McDonald, Robert,Ferguson, Michael J.,Turculet, Laura
-
p. 3818 - 3827
(2019/06/17)
-
- Manganese(III) Porphyrin-Catalyzed Dehydrogenation of Alcohols to form Imines, Tertiary Amines and Quinolines
-
Manganese(III) porphyrin chloride complexes have been developed for the first time as catalysts for the acceptorless dehydrogenative coupling of alcohols and amines. The reaction has been applied to the direct synthesis of imines, tertiary amines and quinolines where only hydrogen gas and/or water are formed as the by-product(s). The mechanism is believed to involve the formation of a manganese(III) alkoxide complex which degrades into the aldehyde and a manganese(III) hydride species. The latter reacts with the alcohol to form hydrogen gas and thereby regenerates the alkoxide complex.
- Azizi, Kobra,Akrami, Sedigheh,Madsen, Robert
-
p. 6439 - 6446
(2019/04/26)
-
- Switching the N-Alkylation of Arylamines with Benzyl Alcohols to Imine Formation Enables the One-Pot Synthesis of Enantioenriched α-N-Alkylaminophosphonates
-
The selective N-alkylation of anilines with benzylic alcohols can be switched in favor of the dehydrogenative condensation process using the nitrile-ligated Kn?lker's complex by conducting the reaction either in a closed system under inert conditions, or in an open system in air. The selective formation of imines, containing reactive C=N bonds, provides an opportunity towards further functionalization. Indeed, a one-pot three-component condensation of alcohols, amines and phosphites, promoted by an iron-based Kn?lker-type complex in combination with a chiral BINOL-based phosphoric acid, provides access to enantioenriched α-N-alkylaminophosphonates.
- Hofmann, Natalie,Hultzsch, Kai C.
-
supporting information
p. 3105 - 3111
(2019/06/08)
-
- Fast continuous alcohol amination employing a hydrogen borrowing protocol
-
A continuous flow method for the direct conversion of alcohols to amines via a hydrogen borrowing approach is reported. The method utilises a low loading (0.5%) of a commercial catalyst system ([Ru(p-cymene)Cl2]2 and DPEPhos), reagent grade solvent and is selective for primary alcohols. Successful methylation of amines using methanol and the direct dimethylamination of alcohols using commercial dimethylamine solution are reported. The synthesis of two pharmaceutical agents Piribedil (5) and Buspirone (25) were accomplished in good yields employing these new methods.
- Labes, Ricardo,Mateos, Carlos,Battilocchio, Claudio,Chen, Yiding,Dingwall, Paul,Cumming, Graham R.,Rincón, Juan A.,Nieves-Remacha, Maria José,Ley, Steven V.
-
supporting information
p. 59 - 63
(2019/01/11)
-
- Half-sandwich ruthenium-carbene catalysts: Synthesis, characterization, and catalytic application in the N-alkylation of amines with alcohols
-
In this study, the synthesis and characterization of new half-sandwich ruthenium complexes containing oxygen functionalised N-aryl and N-alkyl benzimidazol-2-ylidene ligands have been reported. All ruthenium complexes were tested as catalysts for a wide range of substrates in the N-alkylation of secondary cyclic amines such as pyrrolidine and piperidine, and 4-methylaniline which was a primary aromatic amine with alcohols by hydrogen-borrowing process. The catalytic reactions were performed with 1 mol% catalyst loading at 120 °C, 16 h under solvent-free conditions. All ruthenium complexes showed excellent catalytic activity, and N-alkylated products were obtained selectively.
- Kalo?lu, Murat
-
-
- Chemoselective amide reductions by heteroleptic fluoroaryl boron Lewis acids
-
The heteroleptic borane catalyst (C6F5)2B(CH2CH2CH2)BPin is found to hydrosilylatively reduce amides under mild conditions. Simple tertiary amides can be reduced using Me2EtSiH, whereas tertiary benzamides required a more reactive secondary silane, Et2SiH2, for efficient reduction. The catalytic system described exhibits exceptional chemoselectivity in the reduction of oligoamides and tolerates functionalities which are prone to reduction under similar conditions.
- Peruzzi, Michael T.,Mei, Qiong Qiong,Lee, Stephen J.,Gagné, Michel R.
-
supporting information
p. 5855 - 5858
(2018/06/13)
-
- Manganese catalyzed reductive amination of aldehydes using hydrogen as a reductant
-
A one-pot two-step procedure was developed for the alkylation of amines via reductive amination of aldehydes using molecular dihydrogen as a reductant in the presence of a manganese pyridinyl-phosphine complex as a pre-catalyst. After the initial condensation step, the reduction of imines formed in situ is performed under mild conditions (50-100 °C) with 2 mol% of catalyst and 5 mol% of tBuOK under 50 bar of hydrogen. Excellent yields (>90%) were obtained for a large combination of aldehydes and amines (40 examples), including aliphatic aldehydes and amino-alcohols.
- Wei, Duo,Bruneau-Voisine, Antoine,Valyaev, Dmitry A.,Lugan, No?l,Sortais, Jean-Baptiste
-
supporting information
p. 4302 - 4305
(2018/05/03)
-
- Direct Reductive Amination of Carbonyl Compounds with H2 Using Heterogeneous Catalysts in Continuous Flow as an Alternative to N-Alkylation with Alkyl Halides
-
A general continuous-flow procedure for direct reductive amination of secondary and primary amines with aromatic and aliphatic aldehydes as well as ketones is reported. The use of hydrogen gas and commercially available Pt/C as a heterogeneous catalyst is a key. In addition to exhibiting an excellent functional group tolerance, this method allows the fast formation of C?N bonds without production of any hazardous chemical waste. Applications to the synthesis of key intermediates toward active pharmaceutical ingredients (Donepezil and Arformoterol/Tamsulosin) are also described. (Figure presented.).
- Laroche, Benjamin,Ishitani, Haruro,Kobayashi, Shū
-
supporting information
p. 4699 - 4704
(2018/12/04)
-
- Tunable Prussian blue analogues for the selective synthesis of propargylamines through A3 coupling
-
M1[Co(CN)6]2/3-type Prussian blue analogues (M1-Co PBAs) were studied as catalysts for the synthesis of propargylamines via A3 coupling of phenylacetylene, benzaldehyde and piperidine. Cu0.86/su
- Marquez, Carlos,Cirujano, Francisco G.,Van Goethem, Cédric,Vankelecom, Ivo,De Vos, Dirk,De Baerdemaeker, Trees
-
p. 2061 - 2065
(2018/05/03)
-
- Tri(pentaflurophenyl)borane-catalyzed reduction of cyclic imides with hydrosilanes: Synthesis of pyrrolidines
-
B(C6F5)3-catalyzed hydrosilylation of cyclic imides afforded an efficient synthetic method of pyrrolidines. In the presence of 5 mol% B(C6F5)3, various aromatic, aliphatic and polycyclic imides were smoothly reduced by PhSiH3 to generate the corresponding pyrrolidines in high yields. The reaction profiles monitored by 1H NMR spectroscopy disclosed the reduction process of cyclic imides and the effect of difference structure of the hydrosilanes on the hydrosilylation.
- Ding, Guangni,Wu, Xiaoyu,Lu, Bin,Lu, Wenkui,Zhang, Zhaoguo,Xie, Xiaomin
-
p. 1144 - 1150
(2018/02/17)
-
- Synthesizing process of nitrogen-heterocyclic high-selectivity aldehyde
-
The invention relates to a synthesizing process of nitrogen-heterocyclic high-selectivity aldehyde. The synthesizing process is characterized in that when nitrogen-heterocyclic nitrogen atoms have hydrogen atoms, pyrrole, piperidine and pyrazole are used as the initial raw materials, and the pyrrole, the piperidine and the pyrazole are allowed to have reaction with piperidine-1-formaldehyde under nitrogen atom protection to obtain required nitrogen-atom ortho-position aldehyde; when nitrogen-heterocyclic nitrogen atoms have no hydrogen atoms, pyridine and pyrimidine are used to have reaction with the piperidine-1-formaldehyde to obtain the required nitrogen-atom ortho-position aldehyde. The synthesizing process is simple to operate, few in steps and high in selectivity and is a universal method using nitrogen heterocycle to synthesize the nitrogen ortho-position aldehyde.
- -
-
Paragraph 0014; 0017; 0018; 0030; 0033; 0043; 0045
(2017/09/05)
-
- Derisking the Cu-Mediated 18F-Fluorination of Heterocyclic Positron Emission Tomography Radioligands
-
Molecules labeled with fluorine-18 (18F) are used in positron emission tomography to visualize, characterize and measure biological processes in the body. Despite recent advances in the incorporation of 18F onto arenes, the development of general and efficient approaches to label radioligands necessary for drug discovery programs remains a significant task. This full account describes a derisking approach toward the radiosynthesis of heterocyclic positron emission tomography (PET) radioligands using the copper-mediated 18F-fluorination of aryl boron reagents with 18F-fluoride as a model reaction. This approach is based on a study examining how the presence of heterocycles commonly used in drug development affects the efficiency of 18F-fluorination for a representative aryl boron reagent, and on the labeling of more than 50 (hetero)aryl boronic esters. This set of data allows for the application of this derisking strategy to the successful radiosynthesis of seven structurally complex pharmaceutically relevant heterocycle-containing molecules.
- Taylor, Nicholas J.,Emer, Enrico,Preshlock, Sean,Schedler, Michael,Tredwell, Matthew,Verhoog, Stefan,Mercier, Joel,Genicot, Christophe,Gouverneur, Véronique
-
supporting information
p. 8267 - 8276
(2017/06/27)
-
- Efficient and Selective Hydrosilylation of Secondary and Tertiary Amides Catalyzed by an Iridium(III) Metallacycle: Development and Mechanistic Investigation
-
Readily accessible cationic IrIII metallacycles catalyze efficiently the chemoselective hydrosilylation of tertiary and secondary amides to amines. The catalyst described herein operates at low loadings using inexpensive 1,1,3,3-tetramethyldisiloxane and allows fast reactions with high yields, selectivities, and turnover numbers. A transient iminium intermediate has been observed for the first time by using mass spectrometry, and the activation of the catalyst and the silane reagent have been studied by using DFT calculations. These fundamental insights support the present and future improvements of IrIII metallacycles through proper ligand modifications and enable further broad applications of catalysts based on metallacycles.
- Corre, Yann,Trivelli, Xavier,Capet, Frédéric,Djukic, Jean-Pierre,Agbossou-Niedercorn, Francine,Michon, Christophe
-
p. 2009 - 2017
(2017/06/13)
-
- A Manganese Pre-Catalyst: Mild Reduction of Amides, Ketones, Aldehydes, and Esters
-
A new (N-phosphinoamidinate)manganese complex is shown to be a useful pre-catalyst for the hydrosilative reduction of carbonyl compounds, and in most cases at room temperature. The Mn-catalyzed reduction of tertiary amides to tertiary amines, with a useful scope, is demonstrated for the first time by use of this catalyst, and is competitive with the most effective transition-metal catalysts known for such transformations. Ketones, aldehydes, and esters were also successfully reduced under mild conditions by using this new Mn catalyst.
- Kelly, Colin M.,McDonald, Robert,Sydora, Orson L.,Stradiotto, Mark,Turculet, Laura
-
supporting information
p. 15901 - 15904
(2017/12/13)
-
- Cyclometalated palladium pre-catalyst for N-alkylation of amines using alcohols and regioselective alkylation of sulfanilamide using aryl alcohols
-
Simple pyrazole based palladacycle-phosphine with a high turnover has been developed and applied for the N-alkylation of amines and sulfanilamide using alcohols as substrates by hydrogen borrowing strategy. N-alkylation of primary and secondary amines resulted in high isolated yields at 100–130 °C, under solvent free conditions. More challenging secondary aliphatic as well as aromatic alcohols were also successfully utilized as alkylating agents under similar reaction conditions. The turn over number reached up to 43000 for N-benzylation of aniline using benzyl alcohol. Notably, regioselective N-alkylation of 2-aminobenzothiazole and 4-aminobenzenesulfonamide to the corresponding 2-N-(alkylamino)azoles and 4-amino-(N-alkyl)benzenesulfonamides using alcohols as alkylating agents have been achieved using our new pre-catalyst-phosphine system.
- Mamidala, Ramesh,Mukundam, Vanga,Dhanunjayarao, Kunchala,Venkatasubbaiah, Krishnan
-
supporting information
p. 2225 - 2233
(2017/03/24)
-
- Mitsunobu Reaction Using Basic Amines as Pronucleophiles
-
A novel protocol for extending the scope of the Mitsunobu reaction to include amine nucleophiles to form C-N bonds through the utilization of N-heterocyclic phosphine-butane (NHP-butane) has been developed. Both aliphatic alcohols and benzyl alcohols are suitable substrates for C-N bond construction. Various acidic nucleophiles such as benzoic acids, phenols, thiophenol, and secondary sulfonamide also provide the desired products of esters, ethers, thioether, and tertiary sulfonamide with 43-93% yields. Importantly, C-N bond-containing pharmaceuticals, Piribedil and Cinnarizine, have been synthesized in one step from the commercial amines under this Mitsunobu reaction system.
- Huang, Hai,Kang, Jun Yong
-
p. 6604 - 6614
(2017/07/15)
-
- A highly reactive and magnetic recyclable catalyst based on silver nanoparticles supported on ferrite for N-monoalkylation of amines with alcohols
-
Fe3O4@SiO2-Ag catalyst was found to be highly active and selective in the N-alkylation of amines with a variety of aromatic and linear alcohols. The heterogeneous nature of the Fe3O4@SiO2-Ag catalyst allows easy recovery and regeneration by applying an external magnet for six subsequent reaction cycles. The prepared catalyst was characterized using electron microscopy techniques, X-ray diffraction, vibrating sample magnetometry and atomic absorption spectroscopy.
- Bayat, Ahmad,Shakourian-Fard, Mehdi,Nouri, Peyman,Hashemi, Mohammad Mahmoodi
-
-
- Expanding the Boundaries of Water-Tolerant Frustrated Lewis Pair Hydrogenation: Enhanced Back Strain in the Lewis Acid Enables the Reductive Amination of Carbonyls
-
The development of a boron/nitrogen-centered frustrated Lewis pair (FLP) with remarkably high water tolerance is presented. As systematic steric tuning of the boron-based Lewis acid (LA) component revealed, the enhanced back-strain makes water binding increasingly reversible in the presence of relatively strong base. This advance allows the limits of FLP's hydrogenation to be expanded, as demonstrated by the FLP reductive amination of carbonyls. This metal-free catalytic variant displays a notably broad chemoselectivity and generality.
- Dorkó, éva,Szabó, Márk,Kótai, Bianka,Pápai, Imre,Domján, Attila,Soós, Tibor
-
supporting information
p. 9512 - 9516
(2017/08/01)
-
- Colloid and Nanosized Catalysts in Organic Synthesis: XVIII.1 Disproportionation and Cross-Coupling of Amines During Catalysis with Immobilized Nickel Nanoparticles
-
It has been stated that immobilized nickel nanoparticles catalyze disproportionation and cross-coupling of amines. The influence of the support on the catalysis of these properties in the in plug-flow reactor has been studied. The use of active carbon as the support has been found advantageous for the cross-coupling of amines, whereas alumina was a better support for the disproportionation reaction.
- Popov, Yu. V.,Mokhov,Latyshova,Nebykov,Panov,Davydova
-
p. 2757 - 2761
(2018/02/21)
-
- Preparation of Aldehydes by Oxidation of Benzylic Amines with Selectfluor (F-TEDA-BF4)
-
Aldehydes are obtained by mild oxidation of benzylic amines with Selectfluor. The results are compared favorably with the Polonovski-like process using hypervalent iodine.
- Hauser, Anett,Bohlmann, Rolf
-
supporting information
p. 1870 - 1872
(2016/07/16)
-
- Chelating Bis(1,2,3-triazol-5-ylidene) Rhodium Complexes: Versatile Catalysts for Hydrosilylation Reactions
-
NHC-rhodium complexes (NHC=N-heterocyclic carbenes) have been widely used as efficient catalysts for hydrosilylation reactions. However, the substrates were mostly limited to reactive carbonyl compounds (aldehydes and ketones) or carbon-carbon multiple bonds. Here, we describe the application of newly-developed chelating bis(tzNHC)-rhodium complexes (tz=1,2,3-triazol-5-ylidene) for several reductive transformations. With these catalysts, the formal reductive methylation of amines using carbon dioxide, the hydrosilylation of amides and carboxylic acids, and the reductive alkylation of amines using carboxylic acids have been achieved under mild reaction conditions.
- Nguyen, Thanh V. Q.,Yoo, Woo-Jin,Kobayashi, Shu
-
supporting information
p. 452 - 458
(2016/02/12)
-
- Catalytic reductive N-alkylation of amines using carboxylic acids
-
We report a catalytic reductive alkylation reaction of primary or secondary amines with carboxylic acids. The two-phase process involves silane mediated direct amidation followed by catalytic reduction.
- Andrews, Keith G.,Summers, Declan M.,Donnelly, Liam J.,Denton, Ross M.
-
supporting information
p. 1855 - 1858
(2016/02/12)
-
- Scalable synthesis of secondary and tertiary amines by heterogeneous Pt-Sn/γ-Al2O3catalyzed N-alkylation of amines with alcohols
-
Synthesis of secondary and tertiary amines has been efficiently realized from the N-alkylation of amines with alcohols by means of heterogeneous bimetallic Pt-Sn/γ-Al2O3catalyst (0.5?wt % Pt, molar ratio Pt:Sn?=?1:3) through a borrowing hydrogen strategy. The Pt-Sn/γ-Al2O3catalyst has exhibited very high catalytic activity towards a wide range of amines and alcohols, and can be conveniently recycled without Pt metal leaching. The present protocol was applied for the synthesis of N-phenylbenzylamine in 96% isolated yield from aniline and benzyl alcohol on a 2.1?kg scale of the substrates, demonstrating its potential applicability for higher-order amine synthesis.
- Wu, Kaikai,He, Wei,Sun, Chenglin,Yu, Zhengkun
-
supporting information
p. 8516 - 8521
(2016/11/28)
-
- Pd/C as an Efficient and Reusable Catalyst for the Selective N-Alkylation of Amines with Alcohols
-
An efficient Pd/C-catalyzed synthesis of secondary amines involving C-N bond formation was achieved from amines and alcohols with H2O as the only byproduct. This common, green, commercial, and cheap catalyst was recycled five times in this sustainable, simple, and economic procedure.
- Liu, Xiang,Hermange, Philippe,Ruiz, Jaime,Astruc, Didier
-
p. 1043 - 1045
(2016/04/05)
-
- Benzylamines via Iron-Catalyzed Direct Amination of Benzyl Alcohols
-
Benzylamines play a prominent role in numerous pharmaceutically active compounds. Thus, the development of novel, sustainable catalytic methodologies to provide access to these privileged structural motifs is of central importance. Herein we describe a systematic study for the construction of a large variety of benzylamines using a well-defined homogeneous iron complex. The methodology consists of the direct coupling of readily available benzyl alcohols with simpler amines through the borrowing hydrogen methodology, producing a variety of substituted secondary and tertiary benzylamines in moderate to excellent yields for the first time with an iron catalyst. Notably, we explore the versatility of this methodology in the one-pot synthesis of nonsymmetric tertiary amines, sequential functionalization of diols with distinctly different amines, and the synthesis of N-benzyl piperidines via various synthetic pathways. In addition, direct conversion of the renewable building block 2,5-furan-dimethanol to pharmaceutically relevant compounds is achieved.
- Yan, Tao,Feringa, Ben L.,Barta, Katalin
-
p. 381 - 388
(2016/01/12)
-