- Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
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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)
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- Chemoselective Reduction of Tertiary Amides by 1,3-Diphenyl disiloxane (DPDS)
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A convenient procedure for the chemoselective reduction of tertiary amides at room temperature in the presence of air and moisture using 1,3-diphenyldisiloxane (DPDS) is developed. The reaction conditions tolerate a significant number of functional groups including esters, nitriles, secondary amides, carbamates, sulfoxides, sulfones, sulfonyl fluorides, halogens, aryl-nitro groups, and arylamines. The conditions reported are the mildest to date and utilize EtOAc, a preferred solvent given its excellent safety profile and lower environmental impact. The ease of setup and broad chemoselectivity make this method attractive for organic synthesis, and the results further demonstrate the utility of DPDS as a selective reducing agent.
- Aldrich, Courtney C.,Hammerstad, Travis A.,Hegde, Pooja V.,Wang, Kathleen J.
-
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- Iodine-Mediated Coupling of Cyclic Amines with Sulfonyl Hydrazides: an Efficient Synthesis of Vinyl Sulfone Derivatives
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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
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supporting information
p. 701 - 708
(2020/12/30)
-
- 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
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- Intramolecular Csp3-H/C-C bond amination of alkyl azides for the selective synthesis of cyclic imines and tertiary amines
-
The intramolecular Csp3-H and/or C-C bond amination is very important in modern organic synthesis due to its efficiency in the construction of diversified N-heterocycles. Herein, we report a novel intramolecular cyclization of alkyl azides for the synthesis of cyclic imines and tertiary amines through selective Csp3-H and/or C-C bond cleavage. Two C-N single bonds or a CN double bond are efficiently constructed in these transformations. The carbocation mechanism differs from the reported metal nitrene intermediates and therefore enables metal-free and new transformation.
- Jiao, Ning,Li, Xinyao,Luo, Xiao,Song, Song,Wang, Weijin,Wen, Xiaojin
-
p. 4482 - 4487
(2020/05/18)
-
- Controlled Reduction of Carboxamides to Alcohols or Amines by Zinc Hydrides
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New protocols for controlled reduction of carboxamides to either alcohols or amines were established using a combination of sodium hydride (NaH) and zinc halides (ZnX2). Use of a different halide on ZnX2 dictates the selectivity, wherein the NaH-ZnI2 system delivers alcohols and NaH-ZnCl2 gives amines. Extensive mechanistic studies by experimental and theoretical approaches imply that polymeric zinc hydride (ZnH2)∞ is responsible for alcohol formation, whereas dimeric zinc chloride hydride (H?Zn?Cl)2 is the key species for the production of amines.
- Ong, Derek Yiren,Yen, Zhihao,Yoshii, Asami,Revillo Imbernon, Julia,Takita, Ryo,Chiba, Shunsuke
-
supporting information
p. 4992 - 4997
(2019/03/13)
-
- Ruthenium and Iron-Catalysed Decarboxylative N-alkylation of Cyclic Α-Amino Acids with Alcohols: Sustainable Routes to Pyrrolidine and Piperidine Derivatives
-
A modular and waste-free strategy for constructing N-substituted cyclic amines via decarboxylative N-alkylation of α-amino acids employing ruthenium- and iron-based catalysts is presented. The reported method allows the synthesis of a wide range of five- and six-membered N-alkylated heterocycles in moderate-to-excellent yields starting from predominantly proline and a broad range of benzyl alcohols, and primary and secondary aliphatic alcohols. Examples using pipecolic acid for the construction of piperidine derivatives, as well as the one-pot synthesis of α-amino nitriles, are also shown.
- Afanasenko, Anastasiia,Hannah, Rachael,Yan, Tao,Elangovan, Saravanakumar,Barta, Katalin
-
p. 3801 - 3807
(2019/07/31)
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- 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
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p. 3008 - 3012
(2019/05/15)
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- Hitchhiker's Guide to Reductive Amination
-
A comparative study of various widely used methods of reductive amination is reported. Specifically, such reducing agents as H 2, Pd/C, hydride reagents [NaBH 4, NaBH 3 CN, NaBH(OAc) 3 ], and CO/Rh 2 (OAc) 4 system were considered. For understanding the selectivity and activity of the reducing agents reviewed herein, different classes of starting materials were tested, including aliphatic and aromatic amines, as well as aliphatic and aromatic aldehydes and ketones. Most important advantages and drawbacks of the methods, such as selectivity of the target amine formation and toxicity of the reducing agents were compared. Methods were also considered from the viewpoint of green chemistry.
- Afanasyev, Oleg I.,Chusov, Denis,Makarova, Maria,Podyacheva, Evgeniya,Tsygankov, Alexey A.
-
supporting information
p. 2667 - 2677
(2019/06/19)
-
- 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)
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- Concise and Environmentally Friendly Asymmetric Total Synthesis of the Putative Structure of a Biologically Active 3-Hydroxy-2-piperidone Alkaloid
-
An asymmetric total synthesis of stereoisomers of a putative structure of 3-hydroxy-2-piperidone alkaloid derivative is described. This route is not only concise and efficient but also is achieved under an environmentally friendly approach. To this end, a direct and double C-H oxidation reaction of simple benzylated piperidine and Baker's yeast reduction of a carbonyl group allowed the rapid access to the optically enriched (S)-1-benzyl-3-hydroxy-2-piperidone in only three steps. The NMR data agreed with those obtained in the first total synthesis (and in discrepancy with the natural product), however, optical rotation did not match with both neither the natural and synthetic material.
- Romero-Iba?ez, Julio,Cruz-Gregorio, Silvano,Quintero, Leticia,Sartillo-Piscil, Fernando
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p. 2878 - 2886
(2018/07/03)
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- Photoredox-catalyzed Direct Reductive Amination of Aldehydes without an External Hydrogen/Hydride Source
-
The direct reductive amination of aromatic aldehydes has been realized using a photocatalyst under visible light irradiation. The single electron oxidation of an in situ formed aminal species generates the putative α-amino radical that eventually delivers the reductive amination product. This method is operationally simple, highly selective, and functional group tolerant, which allows the direct synthesis of benzylic amines by a unique mechanistic pathway.
- Alam, Rauful,Molander, Gary A.
-
supporting information
p. 2680 - 2684
(2018/05/22)
-
- Fullerenes for catalysis: Metallofullerenes in hydrogen transfer reactions
-
[60]Fullerene hybrids have successfully been used as catalysts in hydrogen transfer reactions, namely ketone reduction and N-alkylation with alcohols. Due to their poor solubility in polar solvents, these hybrids behave as homogeneous/heterogeneous catalysts that can be mechanically separated and reused several times while the final products do not need chromatographic separation.
- Vidal, Sara,Marco-Martínez, Juan,Filippone, Salvatore,Martín, Nazario
-
supporting information
p. 4842 - 4844
(2017/07/06)
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- Transition-Metal-Free Amine Oxidation: A Chemoselective Strategy for the Late-Stage Formation of Lactams
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A metal-free strategy for the formation of lactams via selective oxidation of cyclic secondary and tertiary amines is described. Molecular iodine facilitates both chemoselective and regioselective oxidation of C-H bonds directly adjacent to a cyclic amine. The mild conditions, functional group tolerance, and substrate scope are demonstrated using a suite of diverse small molecule cyclic amines, including clinically approved drug scaffolds.
- Griffiths, Robert J.,Burley, Glenn A.,Talbot, Eric P. A.
-
supporting information
p. 870 - 873
(2017/02/26)
-
- Chelating Bis(1,2,3-triazol-5-ylidene) Rhodium Complexes: Versatile Catalysts for Hydrosilylation Reactions
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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)
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- 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)
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- 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
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p. 381 - 388
(2016/01/12)
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- Palladium nanoparticles stabilised by cinchona-based alkaloids in glycerol: Efficient catalysts for surface assisted processes
-
Palladium nanoparticles (PdNPs) were synthesised and fully characterised, both in solution and the solid state, using naturally-occurring cinchona-based alkaloids in neat glycerol. These nano-systems were stable under reaction conditions, finding applications in hydrogenation and hydrodehalogenation processes, as a result of their surface-like behaviour. Their reactivity was improved in relation to that involving PdNPs stabilised by phosphines and also by Pd/C as a heterogenous catalyst, mainly in terms of recyclability. In particular, the colloidal palladium catalyst stabilised by quinidine was highly efficient to promote the hydrodechlorination of aromatic compounds under low dihydrogen pressure. These original catalysts found applications in the synthesis of secondary and tertiary amines including N-substituted anilines, by means of one-pot tandem Pd-catalysed methodologies under smooth conditions. In all of these processes, glycerol performed a crucial function as a liquid support for the immobilisation of nanoparticle-based catalysts, allowing both the stabilisation of the nano-catalysts and easy recycling of the catalytic phase.
- Reina,Pradel,Martin,Teuma,Gómez
-
p. 93205 - 93216
(2016/10/11)
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- Mild and selective Et2Zn-catalyzed reduction of tertiary amides under Hydrosilylation conditions
-
Diethylzinc (Et2Zn) can be used as an efficient and chemoselective catalyst for the reduction of tertiary amides under mild reaction conditions employing cost-effective polymeric silane (PMHS) as the hydride source. Crucial for the catalytic activity was the addition of a substoichiometric amount of lithium chloride to the reaction mixture. A series of amides containing different additional functional groups were reduced to their corresponding amines, and the products were isolated in good-to-excellent yields.
- Kovalenko, Oleksandr O.,Volkov, Alexey,Adolfsson, Hans
-
supporting information
p. 446 - 449
(2015/03/05)
-
- Preparation of tertiary amines by the reaction of iminium ions derived from unsymmetrical aminals with zinc and magnesium organometallics
-
We report a convenient one-pot preparation of polyfunctional tertiary amines, including various biorelevant phenethylamines or ephedrine derivatives, via the reaction of new functionalized iminium ions with a variety of zinc and magnesium organometallic reagents. These iminium ions were generated from unsymmetrical aminals, obtained by the in situ addition of various amides to Tietzes iminium salt [Me2NCH2+CF3COO-]. A functionalized aniline, prepared by this method, was converted to a quinolidine via an intramolecular Heck reaction.
- Werner, Veronika,Ellwart, Mario,Wagner, Andreas J.,Knochel, Paul
-
supporting information
p. 2026 - 2029
(2015/04/27)
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- Palladium(ii)-catalysed ortho-arylation of N-benzylpiperidines
-
PdII-catalysed ortho-arylation of benzylic heterocycles with arylboronic acid pinacol esters (Ar-BPin) via directed C-H bond activation to generate the desired biaryl products is reported. This methodology is efficient and applicable to a wide range of functionalised Ar-BPin and benzylic heterocycles, allowing the direct synthesis of important biaryl motifs in modest to good yield. This journal is
- Tan, Peng Wen,Haughey, Maxwell,Dixon, Darren J.
-
supporting information
p. 4406 - 4409
(2015/03/18)
-
- Highly efficient and eco-friendly synthesis of tertiary amines by reductive alkylation of aldehydes with secondary amines over a Pt nanowires catalyst
-
Plentiful tertiary amine derivates are synthesized by direct formation of tertiary amines by the interaction of aldehydes with secondary amines over Pt nanowires under mild conditions. This method offers a green and rapid approach to transform secondary amines into various tertiary amines.
- Wu, Junjie,Lu, Shuanglong,Ge, Danhua,Gu, Hongwei
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p. 81395 - 81398
(2015/10/06)
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- Efficient metal-free hydrosilylation of tertiary, secondary and primary amides to amines
-
Hydrosilylation of secondary and tertiary amides to amines is described using catalytic amounts of B(C6F5)3. The organic catalyst enables the reduction of amides with cost-efficient, non-toxic and air stable PMHS and TMDS hydrosilanes. The methodology was successfully extended to the more challenging reduction of primary amides.
- Blondiaux, Enguerrand,Cantat, Thibault
-
supporting information
p. 9349 - 9352
(2014/08/05)
-
- Interfacial hydrogenation and deamination of nitriles to selectively synthesize tertiary amines
-
A novel one-pot method has been developed for the interfacial hydrogenation of nitriles to synthesize asymmetrical tertiary amines. The active Pt NWs allow for the preparation of a series of tertiary amines in excellent yields (up to 99.0%) and a mixed solvent is vital for the adjustment of the yield. And also, the reaction proceeded under mild conditions and is environmentally friendly.
- Lu, Shuanglong,Li, Chao,Wang, Jiaqing,Pan, Yue,Cao, Xueqing,Gu, Hongwei
-
supporting information
p. 11110 - 11113
(2014/10/15)
-
- Regioselective borylation of the C-H bonds in alkylamines and alkyl ethers. Observation and origin of high reactivity of primary C-H bonds beta to nitrogen and oxygen
-
Borylation of aliphatic C-H bonds in alkylamines and alkyl ethers to form primary aminoalkyl and alkoxyalkyl boronate esters and studies on the origin of the regioselectivity of these reactions are reported. The products of these reactions can be used directly in Suzuki-Miyaura cross-coupling reactions or isolated as air-stable potassium trifluoroborate salts. Selective borylation of the terminal C-H bond at the positions β to oxygen and nitrogen occurs in preference to borylation of the other terminal C-H bonds. Experimental studies and computational results show that C-H bond cleavage is the rate-determining step of the current borylation reactions. The observed higher reactivity of C-H bonds at the terminal position of ethylamines and ethers results from a combination of attractive Lewis acid-base and hydrogen-bonding interactions, as well as typical repulsive steric interactions, in the transition state. In this transition state, the heteroatom lies directly above the boron atom of one boryl ligand, creating a stabilizing interaction between the weak Lewis acid and Lewis base, and a series of C-H bonds of the substrate lie near the oxygen atoms of the boryl ligands, participating in a set of weak C- H···O interactions that lead to significant stabilization of the transition state forming the major product.
- Li, Qian,Liskey, Carl W.,Hartwig, John F.
-
supporting information
p. 8755 - 8765
(2014/07/07)
-
- Ultrasound-assisted solventless synthesis of amines by in situ oxidation/reductive amination of benzyl halides
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Ultrasound-assisted solventless oxidation/reductive amination of benzyl halides was developed as a facile, efficient, and environmental friendly method toward N-alkylated amines. Aldehydes were formed in situ by oxidation of organic halides with N-methylmorpholine N-oxide (NMO), followed by direct reductive amination with amines using sodium borohydride and montmorillonite K-10 catalyst as the reducing system. This green and simple procedure enables N-alkylated amines to be prepared in good to excellent yields with high selectivity of the monoalkylation. This journal is the Partner Organisations 2014.
- Khumraksa, Bannarak,Phakhodee, Wong,Pattarawarapan, Mookda
-
p. 20454 - 20458
(2014/06/09)
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- Reusable supported ruthenium catalysts for the alkylation of amines by using primary alcohols
-
Efficient and recyclable ruthenium catalysts were synthesized from readily available polystyrene-or silica-supported phosphine ligands. Catalysts bound to the polymer support through an ether linkage showed good to excellent activity towards the N-alkylation of primary and secondary amines to afford the alkylated products in 62-99 % yield at 120-140°C. The supported phosphine ligand/ruthenium ratio was found to be crucial for higher catalytic activity and lower ruthenium leaching. The continuous flow N-alkylation of amines was demonstrated by using the supported catalyst in a column reactor. By adopting the hydrogen-borrowing strategy, the synthesis of the anti-Parkinson agent Piribedil was established in 98 % yield at 140°C. Support group steals the show: An efficient Ru-based heterogeneous catalyst from readily available supported phosphine ligands is developed. The nature of the linkage and the extent of ruthenium incorporation are crucial in determining the catalytic activity. The catalyst can be recycled and used under continuous flow in a packed-bed reactor. The alkylation of cyclic amines is achieved in excellent yield at moderate temperatures in the absence of any external base.
- Peishan, Siah,Dang, Tuan Thanh,Seayad, Abdul Majeed,Ramalingam, Balamurugan
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p. 808 - 814
(2014/03/21)
-
- Cesium carbonate-catalyzed reduction of amides with hydrosilanes
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Cesium carbonate has been found to be an effective catalyst for the reduction of tertiary carboxamides with the simple, commercially available PhSiH3 under solvent-free conditions. The catalytic system can effectively reduce a range of amides under relatively mild conditions (from room temperature to 80 C) to yield the corresponding amines in good to excellent yields (71-100%) and thus has the potential for practical applications.
- Xie, Weilong,Zhao, Mengdi,Cui, Chunming
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p. 7440 - 7444
(2014/04/03)
-
- Direct hydrosilylation of tertiary amides to amines by an in situ formed iron/N-heterocyclic carbene catalyst
-
Tertiary amides were efficiently reduced to their corresponding tertiary amines in high isolated yields by using the commercially available and inexpensive polymeric silane polymethylhydrosiloxane (PMHS) as the reducing agent. The reaction is efficiently catalyzed by an in situ generated iron/N-heterocyclic carbene complex (1 mol-%) obtained from iron(II) acetate and 1-(2-hydroxy-2-phenylethyl)-3-methylimidazolium triflate ([PhHEMIM][OTF]). A catalytic amount of lithium chloride (1 mol-%) present in the reaction mixture significantly reduced the reaction time and increased the chemoselectivity of the reduction process. Tertiary amides are reduced to their corresponding tertiary amines in high isolated yields by using the polymeric silane polymethylhydrosiloxane (PMHS) in the presence of an in situ generated iron/N-heterocyclic carbene complex (1 mol-%), generated from iron(II) acetate and 1-(2-hydroxy-2-phenylethyl)-3-methylimidazolium triflate ([PhHEMIM][OTF]), and a catalytic amount of lithium chloride (1 mol-%). Copyright
- Volkov, Alexey,Buitrago, Elina,Adolfsson, Hans
-
supporting information
p. 2066 - 2070
(2013/05/09)
-
- Facile and efficient KOH-catalysed reduction of esters and tertiary amides
-
Esters and tertiary amides were efficiently reduced to their corresponding alcohols and amines in high yields under mild and environmentally friendly conditions. The presented KOH-catalysed system involves a simple hydrosilylation procedure that is carried out under solvent-free conditions and does not require the use of inert conditions.
- Fernandez-Salas, Jose A.,Manzini, Simone,Nolan, Steven P.
-
supporting information
p. 9758 - 9760
(2013/10/21)
-
- Microwave-assisted solventless reaction of iridium-catalyzed alkylation of amines with alcohols in the absence of base
-
Microwave-assisted iridium catalyzed alkylation of amines with alcohols was undertaken under solvent-free and base-free conditions. Such alkylation reactions are green, atom-economic, and effective for mono-, di-, and triaklyation of amines. Good isolated yields were obtained for mono- and dialkylated amines using stoichiometric amounts of amines and alcohols, in the presence of 1 mol % [Cp*IrCl2]2. Reasonable yields of trialkylated products were obtained using 4 equiv of alcohols.
- Zhang, Weixing,Dong, Xiaochun,Zhao, Weili
-
supporting information; experimental part
p. 5386 - 5389
(2011/11/29)
-
- Reinvestigation of aminomethyltrifluoroborates and their application in suzuki-miyaura cross-coupling reactions
-
A reinvestigation into the chemical composition of potassium aminomethyltrifluoroborates is reported. These trifluoroborato salts have been reassigned as zwitterionic ammoniomethyltrifluoroborates. Minor adjustments to the previously disclosed reaction conditions are reported that permit a similar level of activity as nucleophiles in Suzuki-Miyaura cross-coupling reactions.
- Raushel, Jessica,Sandrock, Deidre L.,Josyula, Kanth V.,Pakyz, Deborah,Molander, Gary A.
-
experimental part
p. 2762 - 2769
(2011/06/17)
-
- Cross-coupling of mesylated phenol derivatives with potassium ammonio-and amidomethyltrifluoroborates
-
A large array of aryl and heteroaryl mesylates have been successfully employed as electrophiles in a Csp2-Csp3 Suzuki-Miyaura cross-coupling with potassium ammonio-and amidomethyltrifluoroborates to afford the corresponding products
- Molander, Gary A.,Beaumard, Floriane
-
supporting information; experimental part
p. 1242 - 1245
(2011/05/03)
-
- Liquid ammonia as a dipolar aprotic solvent for aliphatic nucleophilic substitution reactions
-
The rate constants for the reactions of a variety of nucleophiles reacting with substituted benzyl chlorides in liquid ammonia (LNH3) have been determined. To fully interpret the associated linear free-energy relationships, the ionization constants of phenols ions in liquid ammonia were obtained using UV spectra. These equilibrium constants are the product of those for ion-pair formation and dissociation to the free ions, which can be separated by evaluating the effect of added ammonium ions. There is a linear relationship between the pKa of phenols in liquid ammonia and those in water of slope 1.68. Aminium ions exist in their unprotonated free base form in liquid ammonia and their ionization constants could not be determined by NMR. The rates of solvolysis of substituted benzyl chlorides in liquid ammonia at 25 °C show a Hammett ρ of zero, having little or no dependence upon ring substituents, which is in stark contrast with the hydrolysis rates of substituted benzyl halides in water, which vary 107 fold. The rate of substitution of benzyl chloride by substituted phenoxide ions is first order in the concentration of the nucleophile indicative of a SN2 process, and the dependence of the rate constants on the pKa of the phenol in liquid ammonia generates a Bronsted βnuc = 0.40. Contrary to the solvolysis reaction, the reaction of phenoxide ion with 4-substituted benzyl chlorides gives a Hammett ρ = 1.1, excluding the 4-methoxy derivative, which shows the normal positive deviation. The second order rate constants for the substitution of benzyl chlorides by neutral and anionic amines show a single Bronsted βnuc = 0.21 (based on the aqueous pKa of amine), but their dependence on the substituent in substituted benzyl chlorides varies with a Hammett ρ of 0 for neutral amines, similar to that seen for solvolysis, whereas that for amine anions is 0.93, similar to that seen for phenoxide ion.(Figure Presented)
- Ji, Pengju,Atherton, John,Page, Michael I.
-
supporting information; scheme or table
p. 1425 - 1435
(2011/04/23)
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- Zinc-catalyzed reduction of amides: Unprecedented selectivity and functional group tolerance
-
(Chemical Equation Presented) A novel zinc-catalyzed reduction of tertiary amides was developed. This system shows remarkable chemoselectivity and substrate scope tolerating ester, ether, nitro, cyano, azo, and keto substituents. Copyright
- Das, Shoubhik,Addis, Daniele,Zhou, Shaolin,Junge, Kathrin,Beller, Matthias
-
supporting information; experimental part
p. 1770 - 1771
(2010/04/25)
-
- An expedient three-component synthesis of tertiary benzylamines
-
A Mannich-like zinc-mediated three-component reaction of aromatic halides, amines, and paraformaldehyde is described. This procedure, which involves the in situ formation of arylzinc reagents, allows the straightforward synthesis of a range of functionalized tertiary benzylamines. Georg Thieme Verlag Stuttgart.
- Le Gall, Erwan,Decompte, Alexandre,Martens, Thierry,Troupel, Michel
-
experimental part
p. 249 - 254
(2010/04/05)
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- Scope of aminomethylations via Suzuki-Miyaura cross-coupling of orsanotrifluoroborates
-
(Chemical Equation Presented) We previously reported the Suzuki-Miyaura reaction of N,N-dialkylaminomethyltrifluoroborates with aryl bromides. Herein, we report a further investigation of the scope and limitations of this palladium-catalyzed aminomethylation reaction. Aryl chlorides, iodides, and triflates coupled in good to excellent yields to give N,N-dialkylbenzylic amines. The aminomethylation of alkenyl bromides was also examined.
- Molander, Gary A.,Gormisky, Paul E.,Sandrock, Deidre L.
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p. 2052 - 2057
(2008/09/19)
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- Aminomethylations via cross-coupling of potassium organotrifluoroborates with aryl bromides
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Equation presented The Suzuki-Miyaura cross-coupling reaction of N,N-dialkylaminomethyltrifluoroborates with aryl halides allows the construction of an aminomethyl aryl linkage through a disconnection based on dissonant reactivity patterns. A variety of t
- Molander, Gary A.,Sandrock, Deidre L.
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p. 1597 - 1600
(2008/02/02)
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- Reductive amination of carbonyl compounds using NaBH4 in a Br?nsted acidic ionic liquid
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Reductive amination of carbonyl compounds using sodium borohydride is conducted in the Br?nsted acidic ionic liquid, 1-methyl imidazolium tetrafluoroborate ([HMIm][BF4]). The ionic liquid plays the dual role of solvent as well as catalyst for efficient conversion of aldehydes and ketones to amines in excellent yields without the formation of side products.
- Reddy, P. Srinivasa,Kanjilal, Sanjit,Sunitha,Prasad, Rachapudi B.N.
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p. 8807 - 8810
(2008/03/18)
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- Method for producing amines by homogeneously catalyzed reductive amination of carbonyl compounds
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The invention relates to the preparation of chiral or achiral amines by reaction of aldehydes or ketones with ammonia or primary or secondary amines in the presence of hydrogen and in the presence of homogeneous metal catalysts under mild conditions. Metal catalysts which can be used are complexes of late transition metals with chiral or achiral phosphorus-containing ligands.
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Page/Page column 12; 17-18
(2010/02/11)
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- A Scrutiny on the Reductive Amination of Carbonyl Compounds Catalyzed by Homogeneous Rh(I) Diphosphane Complexes
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The reductive amination of a series of aldehydes with secondary amines and H2 in the presence of a homogeneous Rh-diphosphane catalyst was studied in order to establish a general mechanism of this reaction and to identify conditions for the improvement of the amine/alcohol ratio in the product. Several possible intermediates as constituents of changing equilibria like half-aminals, N,O-acetals and aminals were observed in the reaction mixture by means of 1H NMR spectroscopy. In individual trials, these compounds could be successfully hydrogenated under the conditions applied for reductive amination (50 bar H2 pressure, MeOH). Some evidence is accumulated that half-aminals and N,O-acetals might be key intermediates of the reductive amination. Moreover, it was found that the formation of the undesired product alcohol is likely based on the reduction of the starting carbonyl compound. However, due to numerous equilibria consisting of several intermediates, general conclusions are hard to be drawn. Proof will be given that, in several cases, the efficiency of the reductive amination of aliphatic aldehydes can be significantly improved by prehydrogenation of the cationic [Rh(dppb)(COD)]+ complex.
- Tararov, Vitali I.,Kadyrov, Renat,Riermeier, Thomas H.,Boerner, Armin
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p. 200 - 208
(2007/10/03)
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- Direct Reductive Amination of Aldehydes and Ketones Using Phenylsilane: Catalysis by Dibutyltin Dichloride
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(matrix presented) A procedure for direct reductive amination of aldehydes and ketones was developed which uses phenylsilane as a stoichiometric reductant and dibutyltin dichloride as a catalyst. Suitable amines included anilines and dialkylamines but not monoalkylamines.
- Apodaca, Richard,Xiao, Wei
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p. 1745 - 1748
(2007/10/03)
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- On the reductive amination of aldehydes and ketones catalyzed by homogeneous Rh(I) complexes
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The homogeneously catalyzed reductive amination of aldehydes and ketones under smooth conditions is reported, showing for the first time, that Rh(I) catalysts based on chelating diphosphines and diphosphinites can be advantageously employed for this reaction, even for the production of chiral amino acid derivatives.
- Tararov,Kadyrov,Riermeier,Borner
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p. 1867 - 1868
(2007/10/03)
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- Manipulation of substituents at nitrogen in tropanes, homotropanes, and dehydro- derivatives
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Trop-6-ene (8-methyl-8-azabicyclo[3.2.1]oct-6-ene) and substituted N- benzylnortrop-6-enes are synthesised. N-Debenzylation of tropanes fails using a wide variety of non-hydrogenolytic conditions despite effective application in model piperidine derivatives; debenzylation of homotropanes is more successful, giving norhomotropane and norhomotrop-7-ene. Bridged N-benzyl compounds react more slowly than N-methyl analogues with chloroformates; the resulting quaternary intermediates are more prone than the N-methyl analogues to suffer competitive reversion to the starting amine, especially in the tropanes, consistent with slower S(N)2 attack at the benzylic carbon during decomposition; the use of an N-p-methoxybenzyl group does allow partial debenzylation to nortrop-6-ene, suggesting greater S(N)1 character in the decomposition step in this case. 'Equatorial' attack is preferred in methylation of N-benzyl-nortrop-6-ene and -homotrop-7-ene with CH3I; subsequent reductive debenzylation of the quaternary salt achieves overall replacement of N-benzyl by N-methyl in both cases. VT NMR studies show the presence of a single 'equatorial' invertomer (CI syn- to the 2C-bridge) in N- chloro-norhomotropanes and -7-enes and by analogy, in the N-alkyl compounds.
- Howarth, Nicola M.,Malpass, John R.,Smith, Craig R.
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p. 10899 - 10914
(2007/10/03)
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- Kinetics and Mechanisms of Nucleophilic Displacements with Heterocycles as Leaving Groups. Part 5. Solvent Effects
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First- and second-order rates for the reactions of 1-methyl-, 1-isopropyl-, 1-s-butyl-, 1-benzyl-, and 1-p-methoxybenzyl-2,4,6-triphenylpyridiniums with piperidine in chlorobenzene in protic and dipolar aprotic solvents are reported.For the 1-isopropyl, 1-s-butyl and 1-p-methoxybenzyl derivatives the bimolecular reaction is accompanied by a unimolecular process in all solvents.Second-order rate constants for the 1-methyl and for the 1-benzyl compounds are correlated with the ET solvent parameter.Principal component analysis of second-order rates provided a three-component model.The first component differentiates aprotic solvents from protic ones, while the second component is linearly related to the basicity parameter B for aprotic solvents.
- Musumarra, Giuseppe,Ballistreri, Francesco P.,Muratore, Salvatore,Katritzky, Alan R.,Wold, Svante
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p. 1049 - 1054
(2007/10/02)
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