- Reversal of polarity by catalytic SET oxidation: Synthesis of azabicyclo[: M. n.0]alkanes via chemoselective reduction of amidines
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A one-pot catalytic method has been developed for the stereoselective synthesis of cyclopropane-fused cyclic amidines using CuBr2/K2S2O8 as an efficient single electron transfer (SET) oxidative system. The generality of this mild method is demonstrated with a wide variety of substrates to furnish pharmaceutically important amidines containing aza-bicyclic and novel aza-tricyclic frameworks in very good yields. A chemoselective reduction of cyclic amidines to 2-/3-azabicyclo[m.n.0]alkanes and octahydroindoles has been developed using a NaBH4/I2 reagent system. The synthetic scope of the chemoselective reduction of the amidine functionality has been exemplified in the stereoselective synthesis of an iminosugar based (±)-epiquinamide analogue. This journal is
- Devarahosahalli Veeranna, Kirana,Kanti Das, Kanak,Baskaran, Sundarababu
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- A potassium magnesiate complex: Synthesis, structure and catalytic intermolecular hydroamination of styrenes
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A new heterobimetallic potassium magnesiate complex KMg[N(SiMe3)2]2Bn (Bn = PhCH2-) was synthesized by simply mixing magnesium amide and potassium benzyl in toluene. The TMEDA-ligated potassium magnesiate comple
- Guan, Bing-Tao,Liu, Yu-Feng,Zhai, Dan-Dan,Zhang, Xiang-Yu
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supporting information
(2022/01/19)
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- B(C6F5)3-catalyzed tandem protonation/deuteration and reduction of: In situ -formed enamines
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A highly efficient B(C6F5)3-catalyzed tandem protonation/deuteration and reduction of in situ-formed enamines in the presence of water and pinacolborane was developed. Regioselective β-deuteration of tertiary amines was achieved with high chemo- and regioselectivity. D2O was used as a readily available and cheap source of deuterium. Mechanistic studies indicated that B(C6F5)3 could activate water to promote the protonation and reduction of enamines. This journal is
- Wu, Rongpei,Gao, Ke
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p. 4032 - 4036
(2021/05/19)
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- Synthesis of Arylethylamines via C(sp3)-C(sp3) Palladium-Catalyzed Cross-Coupling
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Substituted arylethylamines represent a key structural motif in natural, pharmaceutical, and agrochemical compounds. Access to such scaffolds has been the subject of long-standing synthetic interest. Herein, we report the synthesis of such scaffolds via a palladium-catalyzed C(sp3)-C(sp3) coupling between (chloromethyl)aryls and air-/moisture-stable N,N-dialkylaminomethyltrifluoroborate salts. Rapid hit identification was achieved using microscale high-throughput experimentation and was followed by millimolar-scale reaction parameter optimization. A range of structurally and electronically varied arylethylamine products were obtained in moderate to excellent yields (27-96%, >60 examples). The reaction mechanism is proposed to proceed via formation of a trialkylbenzylammonium species prior to oxidative addition.
- Lippa, Rhys A.,Battersby, David J.,Murphy, John A.,Barrett, Tim N.
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p. 3583 - 3604
(2021/02/27)
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- Method of producing higher amine (by machine translation)
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PROBLEM TO BE SOLVED: To provide a method of producing a secondary or tertiary higher amine. SOLUTION: The method of producing a higher amine comprises allowing a primary or secondary amine to react with an alcohol in the presence of at least one species of hydrogen halide selected from hydrogen chloride, hydrogen bromide and hydrogen iodide, or in the presence of a compound capable of producing a hydrogen halide (such as 1,3,5-triazo-2,4,6-triphosphorine-2,2,4,4,6,6-chloride). If the raw material amine is a primary amine, a secondary higher amine and a tertiary higher amine can be produced. If the raw material amine is a secondary amine, a tertiary higher amine can be produced. COPYRIGHT: (C)2012,JPO&INPIT
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Paragraph 0048; 0108; 0109
(2016/10/08)
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- Formal anti-markovnikov hydroamination of terminal aryl alkynes with pinacolborane and hydroxylamines via Zr/Cu sequential catalysis
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We have explored a novel dry plasma process for the fabrication of electrodes on Nafion surfaces. Nanosized pillar structures were prepared through argon ion (Ar+) plasma treatment. The shear strengths of Au electrodes on plasma-treated Nafion surfaces were investigated. We found that the maximum shear strength (1.08 MPa) of Au-Nafion was observed under the optimal conditions (8 min, 100 W, 5 Pa, Ar+). Finally, we successfully prepared strongly bonded Au electrodes on Nafion through plasma surface treatment without using a wet plating process.
- Sakae, Ryosuke,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
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supporting information
p. 1128 - 1130
(2013/10/22)
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- Coupling of two multistep catalytic cycles for the one-pot synthesis of propargylamines from alcohols and primary amines on a nanoparticulated gold catalyst
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A one-pot reaction was performed with a nanoparticulated gold catalyst. A secondary amine is formed through N-monoalkylation of a primary amine with an alcohol by a borrowing hydrogen methodology in a three-step reaction. The secondary amine formed enters into a second A3-coupling cycle to give propargylamines. The multistep reaction requires a gold species formed and stabilized on a ceria surface. Copyright
- Corma, Avelino,Navas, Javier,Sabater, Maria J.
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p. 14150 - 14156
(2013/01/15)
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- Heavier alkaline earth catalysts for the intermolecular hydroamination of vinylarenes, dienes, and alkynes
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The heavier group 2 complexes [M{N(SiMe3)2} 2]2(1, M = Ca; 2, M = Sr) and [M{CH(SiMe3) 2}2(THF)2] (3, M = Ca; 4, M = Sr) are shown to be effective precatalysts for the intermolecular hydroamination of vinyl arenes and dienes under mild conditions. Initial studies revealed that the amide precatalysts, 1 and 2, while compromised in terms of absolute activity by a tendency toward transaminative behavior, offer greater stability toward polymerization/oligomerization side reactions. In every case the strontium species, 2 and 4, were found to outperform their calcium congeners. Reactions of piperidine with para-substituted styrenes are indicative of rate-determining alkene insertion in the catalytic cycle while the ease of addition of secondary cyclic amines was found to be dependent on ring size and reasoned to be a consequence of varying amine nucleophilicity. Hydroamination of conjugated dienes yielded isomeric products via η3-allyl intermediates and their relative distributions were explained through stereoelectronic considerations. The ability to carry out the hydroamination of internal alkynes was found to be dramatically dependent upon the identity of the alkyne substituents while reactions employing terminal alkynes resulted in the precipitation of insoluble and unreactive group 2 acetylides. The rate law for styrene hydroamination with piperidine catalyzed by [Sr{N(SiMe3) 2}2]2 was deduced to be first order in [amine] and [alkene] and second order in [catalyst], while large kinetic isotope effects and group 2 element-dependent ΔS? values implicated the formation of an amine-assisted rate-determining alkene insertion transition state in which there is a considerable entropic advantage associated with use of the larger strontium center.
- Brinkmann, Christine,Barrett, Anthony G. M.,Hill, Michael S.,Procopiou, Panayiotis A.
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supporting information; experimental part
p. 2193 - 2207
(2012/03/10)
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- Base-catalyzed anti-Markovnikov hydroamination of vinylarenes - Scope, limitations and computational studies
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The hydroamination of vinylarenes with primary and secondary amines was studied with catalytic amounts as low as 2 mol-% of LiN(SiMe3) 2/TMEDA. Reactions proceeded readily at 120°C in the absence of solvent to give selective anti-Markovnikov addition. Slow addition was observed at 25°C with either electron-deficient p-chlorostyrene or secondary cyclic amines such as pyrrolidine, piperidine, or morpholine. Primary amines were prone to a second hydroamination reaction to form tertiary amine byproducts. The selectivity for the mono(hydroamination) products could be improved with a two-fold excess of the amine. KN(SiMe3)2 showed higher catalytic activity but lower selectivity in comparison to that of LiN(SiMe 3)2, resulting in undesired C-H-activation by-products. The mechanism of the lithium-catalyzed hydroamination and the influence of TMEDA was studied with density functional theory. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Horrillo-Martinez, Patricia,Hultzsch, Kai C.,Gil, Adria,Branchadell, Vicenc
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p. 3311 - 3325
(2008/02/10)
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- Selective N,N-dibenzylation of primary aliphatic amines with dibenzyl carbonate in the presence of phosphonium salts
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In the presence of catalytic amounts of tetraalkylphosphonium salts and under solventless conditions, primary aliphatic amines (RNH2: R = PhCH2, Ph(CH2)2, n-decyl, and 1-naphthylmethyl) are efficiently N-benzylated to the corresponding RN(CH2Ph) 2, using dibenzyl carbonate as the benzylating reagent. Compared to the reaction run without salt, where the competitive formation of the benzyl carbamate is favored, the phosphonium salt promotes high selectivity toward the benzylated amine and an increase of the reaction rate as well. However, in a single case explored for an amino acidic compound, namely 4-(aminomethyl) benzoic acid [4-(NH2CH2)C6H4CO 2H], both N,N-dibenzylation and esterification of the acid group were observed. Analysis of the IR vibrational modes of benzylamine in the presence of tetrabutylphosphonium bromide supports the hypothesis that this enhanced selectivity may be due to an acid-base interaction between the salt and the amine, which increases the steric bulk of the amine and favors attack of the nucleophile on the less hindered alkyl terminus of dibenzyl carbonate.
- Loris, Alessandro,Perosa, Alvise,Selva, Maurizio,Tundo, Pietro
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p. 3953 - 3956
(2007/10/03)
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- Cesium effect: High chemoselectivity in direct N-alkylation of amines
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A novel method for the mono-N-alkylation of primary amines, diamines, and polyamines was developed using cesium bases in order to prepare secondary amines efficiently. A cesium base not only promoted alkylation of primary amines but also suppressed overalkylations of the produced secondary amines. Various amines, alkyl bromides, and alkyl sulfonates were examined, and the results demonstrated this methodology was highly chemoselective to favor mono-N-alkylation over dialkylation. In particular, use of either sterically demanding substrates or amino acid derivatives afforded the secondary amines exclusively, offering wide applications in peptidomimetic syntheses.
- Salvatore, Ralph Nicholas,Nagle, Advait S.,Kyung, Woon Jung
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p. 674 - 683
(2007/10/03)
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- Cesium Hydroxide Promoted Chemoselective N-Alkylation for the Generally Efficient Synthesis of Secondary Amines
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(Matrix presented) Selective N-alkylation of primary amines was developed using cesium hydroxide to prepare various secondary amines efficiently. A cesium base not only promoted monoalkylations of primary amines but also suppressed overalkylations. Various amines and alkyl bromides were examined, and the preliminary results demonstrated this methodology was highly chemoselective, favoring mono-N-alkylation over dialkylation. In particular, use of amino acid derivatives afforded the desired secondary amines exclusively.
- Salvatore, Ralph N.,Nagle, Advait S.,Schmidt, Shaun E.,Jung, Kyung Woon
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p. 1893 - 1896
(2008/02/11)
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- Enantioselective synthesis of 1,2-diamines via nucleophilic 1,2-addition to dibenzylamino-acetaldehyde-SAMP-hydrazone
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Nucleophilic 1,2-addition of RM/CeCl3 in THF or allyl Grignard reagent in toluene to dibenzylamino-acetaldehyde-SAMP-hydrazone 2 after reductive N-N bond cleavage leads to differently protected 1,2-diamines 4 in good yields and of high enantiomeric purity (ee = 92-99percent).The absolute configuration was determined by X-ray structure analysis on the 1,2-adduct 3e. - Keywords: SAMP-hydrazone; nucleophilic 1,2-addition; asymmetric synthesis; vicinal diamine; organocerium reagent
- Enders, Dieter,Chelain, Evelyne,Raabe, Gerhard
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p. 299 - 306
(2007/10/03)
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- The Chemistry of N-Substituted Benzotriazoles. Part 14. Novel Routes to Secondary and Tertiary Amines and to N,N-Disubstituted Hydroxylamines
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Tertiary amines of types R4R3CHNR1R2 (2), (R2CH2)2NR1 (10) and 11, or (R2CH2)3N (12), secondary amines of type (R2CH2)2NH (8), and N,N-disubstituted hydroxylamines of type (R2CH2)2NOH (9), are prepared in high yield by the action of Grignard reagents or sodium borohydride on easily available N,N-dialkyl-N-amines (1) or tris(benzotriazolylmethyl)amine (7), on bis(benzotriazolylmethyl)amines (3), (5), and (6), and on N,N-bis(benzotriazolylmethyl)hydroxylamine (4), respectively.
- Katritzky, Alan R.,Yannakopoulou, Konstantina,Lue, Ping,Rasala, Danuta,Urogdi, Laszlo
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p. 225 - 233
(2007/10/02)
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