- Origin of 1, 3-induction in the addition of alkyl lithium to imines bearing an N-stereogenic center
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The origin of diastereoselectivity in the addition of alkyl lithium to chiral Schiff bases has been investigated experimentally and theoretically and the formation of the major diastereomer can be explained from the energy minimized structure of the Schiff base in which the phenyl group has been found to orient in such a manner that it posed lesser steric hindrance to the incoming nucleophile as compared to the alkyl group.
- Nancy,Ghosh, Soma,Singh, Nishan,Nanda, Gurmeet Kaur,Venugopalan,Bharatam, Prasad V.,Trehan, Sanjay
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Read Online
- An Iridium Catalytic System Compatible with Inorganic and Organic Nitrogen Sources for Dual Asymmetric Reductive Amination Reactions
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Asymmetric reductive amination (ARA) is one of the most promising methods for the synthesis of chiral amines. Herein we report our efforts on merging two ARA reactions into a single-step transformation. Catalyzed by a complex formed from iridium and a steric hindered phosphoramidite, readily available and inexpensive aromatic ketones initially undergo the first ARA with ammonium acetate to afford primary amines, which serve as the amine sources for the second ARA, and finally provide the enantiopure C2-symmetric secondary amine products. The developed process competently enables the successive coupling of inorganic and organic nitrogen sources with ketones in the same reaction system. The Br?nsted acid additive plays multiple roles in this procedure: it accelerates the formation of imine intermediates, minimizes the inhibitory effect of N-containing species on the iridium catalyst, and reduces the primary amine side products.
- Chang, Mingxin,Gao, Zhaofeng,Geng, Huiling,Huang, Haizhou,Liu, Jingwen
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supporting information
p. 27307 - 27311
(2021/11/17)
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- Rapid Multialkylation of Aqueous Ammonia with Alcohols by Heterogeneous Iridium Catalyst under Simple Conditions
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This paper reports the synthesis of tertiary and secondary amines from aqueous ammonia and benzylic alcohols by titania-supported iridium catalyst. It is a successful example of heterogeneous systems at moderate temperature without either additional solvent or high pressure. The catalytic system showed good tolerance to the atmosphere condition and performed rapidly to give tribenzylamine a yield of over 99 % within 6 hours in argon. The crystal structure of titania supports for iridium catalysts strongly affected their activity. The catalysis smoothly proceeded on larger scales. The catalyst could be easily reused and run at least for 5 cycles without significant loss of activity. The highly-dispersed iridium species of less than 2 nm in diameter would be responsible for the excellent catalytic activity. This catalyst is well applicable in multialkylation of aqueous ammonia with various primary and secondary benzylic alcohols.
- Yu, Han,Ma, Lin,Wada, Kenji,Kurihara, Ryohsuke,Feng, Qi,Uemura, Shinobu,Isoda, Kyosuke
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p. 3588 - 3593
(2021/07/02)
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- Method for synthesizing chiral phosphite ligand based on R - 2 - phenylethylamine
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The invention discloses a method for synthesizing chiral phosphite ligand based on R - 2 -phenylethylamine. To the method, R - 2 -phenylethylamine is reacted with acetophenone to obtain the imine intermediate, and then is mixed with H. 2 Under
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- Scalable preparation of stable and reusable silica supported palladium nanoparticles as catalysts for N-alkylation of amines with alcohols
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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.
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p. 141 - 149
(2020/01/06)
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- One-Pot Synthesis of Symmetrical Tertiary and Secondary Amines from Carbonyl Compounds, Ammonium Carbonate and Carbon Monoxide as a Reductant
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Rh-catalyzed one-step synthesis of tertiary and secondary amines from aldehydes and ketones, ammonium carbonate serving as nitrogen source, and carbon monoxide as a reducing agent has been developed. Aliphatic and aromatic aldehydes lead to the corresponding tertiary symmetrical amines in 69–83 % yields. Aromatic and aliphatic ketones lead to the corresponding secondary symmetrical amines which were obtained in 62–79 % yields.
- Muratov, Karim,Afanasyev, Oleg I.,Kuchuk, Ekaterina,Runikhina, Sofiya,Chusov, Denis
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supporting information
p. 6557 - 6560
(2019/10/22)
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- Synthesis of 2-Arylisoindoline Derivatives Catalyzed by Reusable 1,2,4-Triazole Iridium on Mesoporous Silica through a Cascade Borrowing Hydrogen Strategy
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Covalent attachment of a 1,2,4-triazole iridium complex to mesoporous MCM-41 generated a heterogeneous catalyst that was found to be effective in the synthesis of 2-aryl isoindolines, quinolines, cyclic amines, and symmetrical secondary amines through a cascade borrowing hydrogen strategy. Interestingly, the supported heterogeneous iridium catalyst prepared from the 1,2,4-triazole iridium complex and mesoporous MCM-41 exhibited high catalytic activity in the preparation of 2-aryl isoindoline derivatives and symmetrical secondary amines. The catalyst system is highly recyclable for at least five times. Besides the important effect of the triazole, iridium sites grafted on siliceous supports can act as multifunctional catalytic centers and thus greatly enhance the catalytic activity of the catalysts. Furthermore, mechanistic experiments revealed that the reaction is initiated by an initial alcohol dehydrogenation and promoted by an iridium hydride intermediate. Importantly, the direct detection of a diagnostic iridium hydride signal confirmed that the synthesis of 2-aryl isoindolines occurs by a borrowing hydrogen process. This work provides an efficient example of isoindolines synthesis through a borrowing hydrogen strategy.
- Yao, Wei,Ge, Chenyang,Zhang, Yilin,Xia, Xiao-Feng,Wang, Long,Wang, Dawei
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supporting information
p. 16099 - 16105
(2019/11/26)
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- B(C6F5)3-Catalyzed Asymmetric Reductive Amination of Ketones with Ammonia Borane
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The first example of metal-free B(C6F5)3-catalyzed asymmetric reduction amination of ketones with chiral α-methylbenzylamine (α-MBA) using ammonia borane as the reductant is reported. This one-pot method has a broad substrate scope and provides various chiral amines in 81-95% yield with 80-99% de. This protocol was further applied in the total synthesis of cinacalcet.
- Pan, Zhentao,Shen, Leixin,Song, Dingguo,Xie, Zhen,Ling, Fei,Zhong, Weihui
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p. 11502 - 11509
(2018/09/25)
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- Preparation method of chiral amine compounds
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The invention discloses a preparation method of chiral amine compounds. The preparation method of the chiral amine compounds specifically comprises the following steps: adding ketone compounds and chiral auxiliary (S)-a-phenylethylamine or (R)-a-phenylethylamine to an organic solvent to prepare an imine intermediate under the action of a large-steric-hindrance boron catalyst and a water removing agent; adding a reducing agent to the imine intermediate without separation and purification, and preparing the chiral amine compounds with a one-pot method. By calculation, the product yield is 81%-96%, and the highest de value can reach 99%. Compared with the prior art, the use amount of the large-steric-hindrance boron catalyst in the method can be reduced to 0.1 mol%, use of the equivalent metal catalyst is avoided from the source, and the method has the characteristics of being simple to operate, mild in reaction condition, wide in substrate applicability, environmental friendly and the like, and has better application value and potential economic and social benefits.
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- Hydroboration Catalyzed by 1,2,4,3-Triazaphospholenes
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The synthesis and study of the catalytic activity of 1,2,4,3-triazaphospholenes (TAPs) is reported. TAPs represent a more modular scaffold than previously reported diazaphospholenes. TAP halides were shown to catalyze the 1,2 hydroboration of 19 imines, and three α,β unsaturated aldehydes with pinacolborane, including examples that did not undergo hydroboration by previously reported diazaphospholene systems. DFT calculations support a mechanism where a triazaphospholene cation interacts with the substrate, a mechanism distinct from diazaphospholene catalyzed hydroborations.
- Tien, Chieh-Hung,Adams, Matt R.,Ferguson, Michael J.,Johnson, Erin R.,Speed, Alexander W. H.
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supporting information
p. 5565 - 5568
(2017/10/25)
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- Iron catalyzed diastereoselective hydrogenation of chiral imines
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Cyclopentadienone-based iron complexes were used for the first time to successfully catalyze the diastereoselective hydrogenation of enantiopure imines. Chiral amines, including valuable biologically active products, were obtained often as enantiomericall
- Brenna,Rossi,Cozzi,Benaglia
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supporting information
p. 5685 - 5688
(2017/07/22)
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- Triazolylidene-Iridium Complexes with a Pendant Pyridyl Group for Cooperative Metal–Ligand Induced Catalytic Dehydrogenation of Amines
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Two iridium(III) complexes containing a C,N-bidentate pyridyl-triazolylidene ligand were prepared that are structurally very similar but differ in their pendant substituent. Whereas complex 1 contains a non-coordinating pyridyl unit, complex 2 has a phenyl group on the triazolylidene substituent. The presence of the basic pyridyl unit has distinct effects on the catalytic activity of the complex in the oxidative dehydrogenation of benzylic amines, inducing generally higher rates, higher selectivity towards formation of imines versus secondary amines, and notable quantities of tertiary amines when compared to the phenyl-functionalized analogue. The role of the pyridyl functionality has been elucidated from a set of stoichiometric experiments, which demonstrate hydrogen bonding between the pendant pyridyl unit and the amine protons of the substrate. Such Npyr???H?N interactions are demonstrated by X-ray diffraction analysis, 1H NMR, and IR spectroscopy, and suggest a pathway of substrate bond-activation that involves concerted substrate binding through the Lewis acidic iridium center and the Lewis basic pyridyl site appended to the triazolylidene ligand, in agreement with ligand–metal cooperative substrate activation.
- Valencia, Marta,Pereira, Ana,Müller-Bunz, Helge,Belderraín, Tomás R.,Pérez, Pedro J.,Albrecht, Martin
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p. 8901 - 8911
(2017/07/11)
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- Catalytic Asymmetric Reductive Condensation of N–H Imines: Synthesis of C2-Symmetric Secondary Amines
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A highly diastereoselective and enantioselective Br?nsted acid catalyzed reductive condensation of N?H imines was developed. This reaction is catalyzed by a chiral disulfonimide (DSI), uses Hantzsch esters as a hydrogen source, and delivers useful C2-symmetric secondary amines.
- Wakchaure, Vijay N.,List, Benjamin
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supporting information
p. 15775 - 15778
(2016/12/16)
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- Phosphoramidite Ligands Based on Simple 1,2-Diols: Synthesis, Use in Copper-Catalyzed Asymmetric Additions, and Achirotopic Stereogenic Phosphorus Centres
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Phosphoramidite ligands are widely used in catalysis and normally constructed from large C2-symmetrical diols such as BINOL or TADDOL. We report here on new ligands based on a set of simple diols that had been previously overlooked. Ligands based on (S,S)-trans-cyclohexanediol and (R,R)-(+)-1,2-diphenyl-1,2-ethanediol, in combination with both chiral and achiral amines, were tested in 3 different copper-catalyzed asymmetric reactions and up to 89% ee was observed. A different ligand gave the best results in each reaction examined. Using meso-cis-cyclohexanediol and meso-cis-diphenyl-1,2-ethanediol with a chiral non-racemic amine gave diastereomeric ligands bearing achirotopic stereogenic phosphorus atoms which were characterized with the assistance of X-ray crystallography and variable temperature NMR studies. This work provides a new set of ligands that may be useful in some asymmetric reactions when phosphoramidites based on BINOL and TADDOL are ineffective. We also identify a novel stereochemical feature of phosphoramidites that may be useful in asymmetric catalysis and ligand design. (Figure presented.).
- Mistry, Nisha,Fletcher, Stephen P.
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supporting information
p. 2489 - 2496
(2016/08/16)
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- Design of modified amine transfer reagents allows the synthesis of α-chiral secondary amines via CuH-catalyzed hydroamination
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The CuH-catalyzed hydroamination of alkenes and alkynes using a silane and an amine transfer reagent represents a simple strategy to access chiral amine products. We have recently reported methods to prepare chiral amines with high efficiency and stereoselectivity using this approach. However, the current technology is limited to the synthesis of trialkylamines from dialkylamine transfer reagents (R2NOBz). When monoalkylamine transfer reagents [RN(H)OBz] were used for the synthesis of chiral secondary amines, competitive, nonproductive consumption of these reagents by the CuH species resulted in poor yields. In this paper, we report the design of a modified type of amine transfer reagent that addresses this limitation. This effort has enabled us to develop a CuH-catalyzed synthesis of chiral secondary amines using a variety of amine coupling partners, including those derived from amino acid esters, carbohydrates, and steroids. Mechanistic investigations indicated that the modified amine transfer reagents are less susceptible to direct reaction with CuH.
- Niu, Dawen,Buchwald, Stephen L.
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supporting information
p. 9716 - 9721
(2015/08/18)
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- First efficient two-step/one-pot zirconium (IV)isopropoxide-mediated reductive amination of carbonyl compounds
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An efficient method for the synthesis of various primary and secondary amines through a zirconium(IV) isopropoxide-mediated reductive amination reaction of aldehydes and ketones is reported. A series of different aldehydes, ketones and amines were used leading to the expected amino products in moderate to excellent yields. The mechanistic rationale of this reaction has been postulated through the formation of a transient imine species and a diastereoselective version using (R)-phenylethylamine as chiral inducer led to the expected products in moderate to excellent yields and with diastereoselectivities up to 100%.
- Pieri, Cyril,Brunel, Jean Michel
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p. 448 - 456
(2015/06/22)
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- Selective synthesis of primary amines by reductive amination of ketones with ammonia over supported Pt catalysts
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Supported platinum catalysts are studied for the reductive amination of ketones under ammonia and hydrogen. For a model reaction with 2-adamantanone, Pt-loaded MoOx/TiO2 (Pt-MoOx/TiO2) shows the highest yield of primary amine. The catalyst is effective for the selective transformation of various aliphatic and aromatic ketones to the corresponding primary amines, which demonstrates the first example of the selective synthesis of primary amines by this reaction. The yield of the amine increases with increase in the negative shift of the C£O stretching band in the infrared spectra of adsorbed acetone on the catalysts, suggesting that Lewis acid sites on the support material play an important role in this catalytic system.
- Nakamura, Yoichi,Kon, Kenichi,Touchy, Abeda Sultana,Shimizu, Ken-Ichi,Ueda, Wataru
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p. 921 - 924
(2015/03/18)
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- ORGANOMETALLIC COMPOUND HAVING NITROGEN-CONTAINING HETEROCYCLIC CARBENE LIGAND, CATALYST COMPRISING THE SAME, AND METHOD FOR PRODUCING AMINE COMPOUND
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PROBLEM TO BE SOLVED: To provide a novel organometallic compound, a novel catalyst containing the organometallic compound having excellent functional group selectivity to produce an amine compound by a reductive amination reaction or a hydrogenation reaction of an imine or an iminium ion, and a novel method for producing an amine compound using the catalyst. SOLUTION: Provided is an organometallic compound represented by the following general formula (1). [Ar represents an aromatic compound and the like; Q represents a hydrido group and the like; M represents ruthenium, rhodium, and the like; R1 represents an electron withdrawing group; R2 to R6 each independently represent a C1-20 alkyl group and the like; n is an integer of 0 to 3; and A represents a nitrogen-containing saturated heterocyclic carbene and the like containing at least two nitrogen atoms]. COPYRIGHT: (C)2015,JPO&INPIT
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Paragraph 0165
(2016/10/10)
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- Racemisation of 1-arylethylamines with Shvo-type organoruthenium catalysts
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Variation of the electronic nature of the tetraphenylcyclopentadienone ligand in organoruthenium complexes influences their utility for racemisation of model chiral amines. Our study highlights the need to balance reactivity and selectivity in the design of racemisation catalysts. Electron-poor Shvo-type catalysts are, at first sight, more effective for racemisation, but yield more by-product; electron-rich complexes are less proficient at racemisation, but lead to less by-product.
- Apps, James F. S.,Livingston, Andrew G.,Parrett, Mark R.,Pounder, Ryan J.,Taylor, Paul C.,Turner, Andrew R.
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p. 1391 - 1394
(2014/06/23)
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- An approach to chemoenzymatic DKR of amines in Soxhlet apparatus Dedicated to Prof. Maria José Calhorda on the occasion of her 65th birthday.
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The coexistence of thermolabile enzyme and metal catalyst for racemization of amines in chemoenzymatic dynamic kinetic resolution, requiring high temperature of operation, is enabled by carrying out the reaction in modified Soxhlet extraction system. Init
- Mavrynsky, Denys,Leino, Reko
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p. 161 - 166
(2014/05/06)
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- N-alkylation of ammonia and amines with alcohols catalyzed by Ni-loaded CaSiO3
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Nickel nanoparticles loaded onto calcium silicate (Ni/CaSiO3) have been prepared by ion-exchange method followed by in situ H 2-reduction of the calcined precursor. Ni/CaSiO3 was found to be effective for the catalytic direct synthesis of primary amines from alcohols and NH3 under relatively mild conditions. Various aliphatic alcohols are tolerated, and the turnover number (TON) was higher than those of Ru-based homogeneous catalysts. The catalyst was recoverable and was reused. Effects of the surface oxidation states and particle size of Ni on the catalytic activity were studied by infrared (IR) investigation of the states of adsorbed CO and transmission electron microscopy (TEM). It is clarified that the surface Ni0 sites on small (3 nm) sized Ni nanoparticles are the catalytically active species. Ni/CaSiO3 was also effective for the alkylation of anilines and aliphatic amines with various alcohols (benzyl and aliphatic alcohols) under additive free conditions; primary amines were converted into secondary amines and secondary amines into tertiary amines.
- Shimizu, Ken-Ichi,Kanno, Shota,Kon, Kenichi,Hakim Siddiki,Tanaka, Hideyuki,Sakata, Yoshihisa
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p. 134 - 138
(2014/06/09)
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- METHOD FOR PRODUCING N-SUBSTITUTED AMINE COMPOUNDS THROUGH CATALYZED ALKYLATION
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The invention relates to a method for producing a N-substituted amine compound by catalyzed alkylation. The method uses amine and alcohol or two kinds of amines as the reaction materials, employs composite metal oxides catalyst at a reaction temperature of 80-180° C. to catalyze the reaction for 6-36 hours, so as to produce the N-substituted amine compound. The reaction condition of the method of the invention is relatively moderate, using a catalyst made of cheap non-noble metals, which is non-caustic and easy to be separated and reused. The reaction does not need any medium and has relatively high conversion rate and selectivity.
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Paragraph 0046
(2014/02/16)
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- Practical synthesis of simplephos ligands: Further development of alkyl-substituted phosphanamines
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Herein we disclose a rapid and easy synthetic procedure to access aryl- and alkyl-substituted phosphanamines (SimplePhos ligands). During the synthesis of a library of diverse aryl-substituted phosphanamine ligands we also found that alkyl-substituted phosphanamines can be synthesized and handled easily. This was unexpected as a previous report described them as highly air-sensitive compounds. Subsequently, we created a library of alkyl-substituted phosphanamines and found some to be highly efficient ligands in copper-catalyzed reactions such as the Cu-catalyzed asymmetric conjugate addition and propargylic alkylation reactions. Moreover, our efforts towards the synthesis of SimplePhos ligands led to the development of an easy and practical synthesis of diaryl(chloro)phosphanes, which is also presented in this paper. Copyright
- Mueller, Daniel,Guenee, Laure,Alexakis, Alexandre
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supporting information
p. 6335 - 6343
(2013/10/21)
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- Step-efficient access to chiral primary amines
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Routes to enantioenriched amines are outlined that employ reductive amination and carbanion addition methods. The strategies require either one or two reaction steps from prochiral carbonyl compounds for the synthesis of the corresponding chiral primary amines. Georg Thieme Verlag Stuttgart New York.
- Nugent, Thomas C.,Marinova, Sofiya M.
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p. 153 - 166
(2013/02/25)
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- An investigation of the observed, but counterintuitive, stereoselectivity noted during chiral amine synthesis via N-chiral-ketimines
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The default explanation for good to high diastereomeric excess when reducing N-chiral imines possessing only mediocre cis/transimine ratios (>15% cis-imine) has invariably been in situ cis-to-trans isomerization before reduction; but until now no study un
- Nugent, Thomas C.,Williams, Richard Vaughan,Dragan, Andrei,Mendez, Alejandro Alvarado,Iosub, Andrei V.
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supporting information
p. 2103 - 2112
(2013/11/19)
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- Development of a general non-noble metal catalyst for the benign amination of alcohols with amines and ammonia
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The N-alkylation of amines or ammonia with alcohols is a valuable route for the synthesis of N-alkyl amines. However, as a potentially clean and economic choice for N-alkyl amine synthesis, non-noble metal catalysts with high activity and good selectivity are rarely reported. Normally, they are severely limited due to low activity and poor generality. Herein, a simple NiCuFeOx catalyst was designed and prepared for the N-alkylation of ammonia or amines with alcohol or primary amines. N-alkyl amines with various structures were successfully synthesized in moderate to excellent yields in the absence of organic ligands and bases. Typically, primary amines could be efficiently transformed into secondary amines and N-heterocyclic compounds, and secondary amines could be N-alkylated to synthesize tertiary amines. Note that primary and secondary amines could be produced through a one-pot reaction of ammonia and alcohols. In addition to excellent catalytic performance, the catalyst itself possesses outstanding superiority, that is, it is air and moisture stable. Moreover, the magnetic property of this catalyst makes it easily separable from the reaction mixture and it could be recovered and reused for several runs without obvious deactivation. Copyright
- Cui, Xinjiang,Dai, Xingchao,Deng, Youquan,Shi, Feng
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supporting information
p. 3665 - 3675
(2013/03/29)
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- Heterogeneous Ni catalyst for direct synthesis of primary amines from alcohols and ammonia
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This paper reports the synthesis of primary amines from alcohols and NH3 by an Al2O3-supported Ni nanoparticle catalyst as the first example of heterogeneous and noble-metal-free catalytic system for this reaction without additional hydrogen sources under relatively mild conditions. Various aliphatic alcohols are tolerated, and turnover numbers were higher than those of Ru-based homogeneous catalysts. The catalyst was recoverable and was reused. The effects of the Ni oxidation states and the acid-base nature of support oxides on the catalytic activity are studied. It is clarified that the surface metallic Ni sites are the catalytically active species, and the copresence of acidic and basic sites on the support surface is also indispensable for this catalytic system.
- Shimizu, Ken-Ichi,Kon, Kenichi,Onodera, Wataru,Yamazaki, Hiroshi,Kondo, Junko N.
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p. 112 - 117
(2013/03/29)
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- Highly efficient heterogeneous gold-catalyzed direct synthesis of tertiary and secondary amines from alcohols and urea
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Urea, the white gold: The efficient synthesis of tertiary and secondary amines is achieved by heterogeneous gold-catalyzed direct amination of stoichiometric alcohols with urea in good to excellent yields. Via a hydrogen autotransfer pathway, the reactions of primary alcohols with urea give tertiary amines exclusively, while secondary alcohols selectively afford secondary amines.
- He, Lin,Qian, Yue,Ding, Ran-Sheng,Liu, Yong-Mei,He, He-Yong,Fan, Kang-Nian,Cao, Yong
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experimental part
p. 621 - 624
(2012/05/20)
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- Selective synthesis of secondary amines by Pt nanowire catalyzed reductive amination of aldehydes and ketones with ammonia
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The process of the reductive amination of aldehydes or ketones in the presence of ammonia using unsupported ultra-thin Pt nanowires has been developed. This catalytic system shows high activity and selectivity under mild reaction conditions.
- Qi, Fenqiang,Hu, Lei,Lu, Shuanglong,Cao, Xueqin,Gu, Hongwei
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p. 9631 - 9633
(2012/10/29)
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- Metal-free transfer hydrogenation catalysis by B(C6F 5)3
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The activation of amines by B(C6F5)3 is shown to effect the catalytic racemization of a chiral amine. Extending this strategy to a bimolecular process, catalytic transfer hydrogenation of imines, enamines, and N-heterocycles is demonstrated using iPr2NH as the source of hydrogen and a catalytic amount of the Lewis acid B(C 6F5)3.
- Farrell, Jeffrey M.,Heiden, Zachariah M.,Stephan, Douglas W.
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scheme or table
p. 4497 - 4500
(2011/11/04)
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- Towards energetically viable asymmetric deprotonations: Selectivity at more elevated temperatures with C2-symmetric magnesium bisamides
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A novel chiral magnesium bisamide has enabled the development of effective asymmetric deprotonation protocols at substantially more elevated temperatures. This new, structurally simple, C2-symmetric magnesium complex displays excellent levels o
- Bennie, Linsey S.,Kerr, William J.,Middleditch, Michael,Watson, Allan J. B.
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supporting information; experimental part
p. 2264 - 2266
(2011/04/12)
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- Sequential reductive amination-hydrogenolysis: A one-pot synthesis of challenging chiral primary amines
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Difficult-to-access chiral primary amines were formed in good to high yield and ee using a rare example of a one-pot synthesis from prochiral ketones (sequential reductive amination-hydrogenloysis). As a highlight we also demonstrate a one-pot reductive amination-hydrogenolysis-reductive amination (five reactions) of ortho-methoxyacetophenone resulting in the chiral diamine 1-(2-methoxyphenyl)ethyl-(2-pyridylmethyl)-amine (4) (58% overall yield, >99% ee), a new organocatalyst for aqueous enantioselective aldol reactions. Copyright
- Nugent, Thomas C.,Negru, Daniela E.,El-Shazly, Mohamed,Hu, Dan,Sadiq, Abdul,Bibi, Ahtaram,Umar, M. Naveed
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supporting information; experimental part
p. 2085 - 2092
(2011/10/19)
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- Transition Metal-Catalyzed C-H Amination Using Unactivated Amines
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One aspect of the invention relates to a method of animation or amidation, comprising the step of combining a substrate, comprising a reactive C—H bond, and an amine or amide, comprising a reactive N—H bond, in the presence of an oxidizing agent and a metal-containing catalyst, thereby forming a product with a covalent bond between the carbon of the reactive C—H bond and the nitrogen of the reactive N—H bond.
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Page/Page column 3; 27
(2011/09/20)
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- Mild nonepimerizing N -alkylation of amines by alcohols without transition metals
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A one-pot two-step sequence involving an oxidation/imine-iminium formation/reduction allowed the N-alkylation of amines by alcohols without any epimerization when optically active alcohols and amines are involved in the process.
- Guerin, Claire,Bellosta, Veronique,Guillamot, Gerard,Cossy, Janine
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supporting information; experimental part
p. 3534 - 3537
(2011/08/10)
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- Selective cross-coupling of amines by alumina-supported palladium nanocluster catalysts
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Al2O3-supported Pd nanoclusters with an average particle size of 1.8 nm act as a reusable catalyst for the selective cross-coupling of amines. The reaction is a structure-sensitive reaction, demanding coordinatively unsaturated Pd atoms on a metallic nanocluster. The support also affects the activity, an amphoteric oxide (Al2O 3) is most effective. The Royal Society of Chemistry.
- Shimizu, Ken-Ichi,Shimura, Katsuya,Ohshima, Keiichiro,Tamura, Masazumi,Satsuma, Atsushi
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supporting information; experimental part
p. 3096 - 3100
(2011/12/04)
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- Metal-free diastereoselective catalytic hydrogenations of imines using B(C6F5)3
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Reductions of chiral ketimines effected under H2 by catalytic amounts of B(C6F5)3 result in moderate to excellent diastereoselectivities. In the case of camphor and menthone derived imines, the reductions procee
- Heiden, Zachariah M.,Stephan, Douglas W.
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supporting information; experimental part
p. 5729 - 5731
(2011/07/08)
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- Pt-Sn/γ-Al2O3-catalyzed highly efficient direct synthesis of secondary and tertiary amines and imines
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Versatile syntheses of secondary and tertiary amines by highly efficient direct N-alkylation of primary and secondary amines with alcohols or by deaminative self-coupling of primary amines have been successfully realized by means of a heterogeneous bimetallic Pt-Sn/γ-Al2O3 catalyst (0.5 wt % Pt, Pt/Sn molar ratio=1:3) through a borrowing-hydrogen strategy. In the presence of oxygen, imines were also efficiently prepared from the tandem reactions of amines with alcohols or between two primary amines. The proposed mechanism reveals that an alcohol or amine substrate is initially dehydrogenated to an aldehyde/ketone or NH-imine with concomitant formation of a [PtSn] hydride. Condensation of the aldehyde/ketone species or deamination of the NH-imine intermediate with another molecule of amine forms an N-substituted imine which is then reduced to a new amine product by the in-situ generated [PtSn] hydride under a nitrogen atmosphere or remains unchanged as the final product under an oxygen atmosphere. The Pt-Sn/γ-Al2O 3 catalyst can be easily recycled without Pt metal leaching and has exhibited very high catalytic activity toward a wide range of amine and alcohol substrates, which suggests potential for application in the direct production of secondary and tertiary amines and N-substituted imines.
- He, Wei,Wang, Liandi,Sun, Chenglin,Wu, Kaikai,He, Songbo,Chen, Jiping,Wu, Ping,Yu, Zhengkun
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experimental part
p. 13308 - 13317
(2012/02/02)
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- The "borrowing hydrogen strategy" by supported ruthenium hydroxide catalysts: Synthetic scope of symmetrically and unsymmetrically substituted amines
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The N-alkylation of ammonia (or its surrogates, such as urea, NH 4HCO3, and (NH4)2CO3) and amines with alcohols, including primary and secondary alcohols, was efficiently promoted under anaerobic conditions by the easily prepared and inexpensive supported ruthenium hydroxide catalyst Ru(OH)x/TiO2. Various types of symmetrically and unsymmetrically substituted "tertiary" amines could be synthesized by the N-alkylation of ammonia (or its surrogates) and amines with "primary" alcohols. On the other hand, the N-alkylation of ammonia surrogates (i.e., urea and NH 2HCO3) with "secondary" alcohols selectively produced the corresponding symmetrically substituted "secondary" amines, even in the presence of excess amounts of alcohols, which is likely due to the steric hindrance of the secondary alcohols and/or secondary amines produced. Under aerobic conditions, nitriles could be synthesized directly from alcohols and ammonia surrogates . The observed catalysis for the present N-alkylation recations was intrinsically heterogeneous, and the retrieved catalyst could be reused without any significant loss of catalytic performance. The present catalytic transformation would proceed through consecutive N-alkylation reactions, in which alcohols act as alkylating reagents. On the basis of deuterium-labeling experiments, the formation of the ruthenium dihydride species is suggested during the N-alkylation reactions.
- Yamaguchi, Kazuya,He, Jinling,Oishi, Takamichi,Mizuno, Noritaka
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scheme or table
p. 7199 - 7207
(2010/09/05)
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- Multialkylation of aqueous ammonia with alcohols catalyzed by water-soluble Cp*Ir-ammine complexes
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Novel water-soluble Cp*Ir-ammine complexes have been synthesized, and a new and highly atom-economical system for the synthesis of organic amines using aqueous ammonia as a nitrogen source has been developed. With a water-soluble and air-stable Cp*Ir-ammine catalyst, [Cp*Ir(NH 3)3][I]2, a variety of tertiary and secondary amines were synthesized by the multialkylation of aqueous ammonia with theoretical equivalents of primary and secondary alcohols. The catalyst could be recycled by a facile procedure maintaining high activity. A one-flask synthesis of quinolizidine starting with 1,5,9-nonanetriol was also demonstrated. This new catalytic system would provide a practical and environmentally benign methodology for the synthesis of various organic amines.
- Kawahara, Ryoko,Fujita, Ken-Ichi,Yamaguchi, Ryohei
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supporting information; experimental part
p. 15108 - 15111
(2010/12/24)
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- A convenient, highly stereoselective, metal-free synthesis of chiral amines
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A low cost, efficient, metal-free highly stereoselective reduction of ketimines to chiral amines was developed. Different imines bearing a very cheap and removable chiral auxiliary were reduced simply by trichlorosilane in the presence of N,N-dimethylformamide, often in quantitative yield and complete control of the absolute stereochemistry, to afford highly enantiomerically enriched amines. Georg Thieme Verlag Stuttgart.
- Guizzetti, Stefania,Benaglia, Maurizio,Biaggi, Cinzia,Celentano, Giuseppe
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supporting information; experimental part
p. 134 - 136
(2010/07/16)
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- PROCESS FOR DIASTEREOSELECTIVE CONVERSION OF CHIRAL IMINES
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Diastereoselective conversion of chiral imines of the formula I to amines of the formula II where the R1 to R4 radicals are each as defined in the description and R1 and R2 are different than one another, by con
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Page/Page column 15-16
(2010/12/26)
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- Highly stereoselective metal-free catalytic reduction of Lmines: An easy entry to enantiomerically pure amines and natural And Unnatural α-amino esters
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A highly efficient catalytic stereoselective ketlmlne reduction is described. The combination of an Inexpensive chiral organocatalyst, easily prepared In a single step, and of a very cheap removable chiral auxiliary allowed us to obtain enantlomerlcally pure amino compounds. The methodology allowed synthesis of chiral secondary and primary amines and natural and unnatural amino esters In high yields often with total control of the absolute stereochemistry.
- Gulzzettl, Stefania,Benagila, Maurizio,Rossi, Sergio
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supporting information; experimental part
p. 2928 - 2931
(2009/12/05)
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- A new atom-economical and selective synthesis of secondary and tertiary alkylamines by means of Cp*Iridium complex catalyzed multiple N-alkylation of ammonium salts with alcohols without solvent
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A new atom-economical and selective synthetic method for secondary and tertiary alkylamines has been achieved by means of (pentamethylcyclopentadienyl) iridium (Cp*Ir) complex catalyzed multiple N-alkylations of ammonium salts with primary and secondary alcohols without solvent. Georg Thieme Verlag Stuttgart.
- Yamaguchi, Ryohei,Mingwen, Zhu,Kawagoe, Shoko,Asai, Chiho,Fujita, Ken-Ichi
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experimental part
p. 1220 - 1223
(2009/12/04)
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- Heterogeneous raney nickel and cobalt catalysts for racemization and dynamic kinetic resolution of amines
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Raney metals were studied as heterogeneous catalysts for racemization and dynamic kinetic resolution (DKR) of chiral amines, as an alternative to metals like palladium or ruthenium. Both Raney nickel and cobalt were able to selectively racemize various chiral amines with high selectivity. In the racemization of benzylic primary amines, the minor formation of side products, e.g., secondary amines, can be suppressed by varying the hydrogen pressure. In the racemization of aliphatic amines over Raney catalysts, the selectivity is very high, with the enantiomeric amine as the sole product. DKR of racemic aliphatic amines can be performed with immobilized Candida antarctica lipase B and Raney nickel in one pot; for 2-hexylamine, a yield of 95% of the acetylated amide was achieved, with 97% ee. Attention is devoted to the compatibility of the enzyme and the metal catalyst during the DKR. For benzylic primary amines, a two-pot process is proposed in which the liquid is alternatingly shuttled between two vessels containing the solid racemization catalyst and the biocatalyst. After 4 such cycles, the amide of (R)-1-phenylethylamine was obtained with 94% yield and more than 90% ee.
- Parvulescu, Andrei N.,Jacobs, Pierre A.,De Vos, Dirk E.
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scheme or table
p. 113 - 121
(2009/04/16)
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- Selective synthesis of secondary and tertiary amines by Cp*iridium-catalyzed multialkylation of ammonium salts with alcohols
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(Chemical Equation Presented) The efficient selective synthesis of secondary and tertiary amines has been achieved by means of Cp*Ir- catalyzed multialkylation of ammonium salts with alcohols without solvent: the reactions of ammonium acetate with alcohols gave tertiary amines exclusively, while those of ammonium tetrafluoroborate afforded secondary amines selectively. Using this method, secondary 5- and 6-membered cyclic amines were synthesized from ammonium tetrafluoroborate and diols in one pot.
- Yamaguchi, Ryohei,Kawagoe, Shoko,Asai, Chiho,Fujita, Ken-Ichi
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p. 181 - 184
(2008/09/18)
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- C-H carbene insertion of α-diazo acetamides by photolysis in non-conventional media
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(Chemical Equation Presented) Light from a mercury vapor high-pressure lamp was used to induce the photolytic decomposition of α-diazo acetamides in hexane and in nonconventional media such as water or a film. The corresponding a- and/or γ-lactams were ob
- Candeias, Nuno R.,Gois, Pedro M. P.,Veiros, Luis F.,Afonso, Carlos A. M.
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p. 5926 - 5932
(2008/12/21)
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- Mixtures of chiral phosphorous acid diesters and achiral P ligands in the enantio- and diastereoselective hydrogenation of ketimines
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Try this cocktail! Ligand systems comprising a monodentate phosphorous acid diester derived from binol (La) and an achiral monodentate P ligand (Lb), such as a phosphite, are surprisingly efficient in the stereoselective Ir-catalyzed hydrogenation of ketimines (see scheme).
- Reetz, Manfred T.,Bondarev, Oleg
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p. 4523 - 4526
(2008/09/17)
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- Synthesis and dynamics of atropisomeric (S)-N-(α-phenylethyl)benzamides
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The synthesis of atropisomeric 2-substituted benzamides 2a-e, 3a-e, and 4a-e, and characterization by X-ray structure analysis of 2d, 2e, 3c, 3e, 4c, and 4e are reported. Dynamic 1H NMR spectroscopic studies of benzamides 2b-d, 3b-d, and 4b-d i
- Huelgas, Gabriela,Bernès, Sylvain,Sánchez, Mario,Quintero, Leticia,Juaristi, Eusebio,Anaya de Parrodi, Cecilia,Walsh, Patrick J.
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p. 12655 - 12664
(2008/03/17)
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- Catalytic racemisation of chiral amines and application in dynamic kinetic resolution
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A mild and efficient procedure for the racemisation of optically active amines has been developed and applied to the dynamic kinetic resolution (DKR) of a racemic amine. Pentamethylcyclopentadienyliridium (III) iodide dimer dissolved in a convenient solvent is the precatalyst that reacts in situ with primary, secondary, or tertiary amines to form what we have named a SCRAM catalyst. This is able to dehydrogenate a substrate amine to form an imine, which, depending upon the reaction conditions, is then reduced back to the amine. When an optically active amine is mixed with the iridium precatalyst, racemisation is observed. The SCRAM catalyst is used under mild conditions compatible with suitable enzymes and acyl donors, and thus the DKR of an amine has been effected, giving significantly higher yield than if the enzyme alone was used. A mixed carbonate was identified as the optimal acyl donor, giving a carbamate product that is readily removed by acidic hydrolysis.
- Blacker, A. John,Stirling, Matthew J.,Page, Michael I.
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p. 642 - 648
(2012/12/31)
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- Asymmetric reductive amination: Convenient access to enantioenriched alkyl-alkyl or aryl-alkyl substituted α-chiral primary amines
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A two-step procedure for producing optically active, high value primary amines has been developed. The first and key step is the asymmetric reductive amination of a prochiral alkyl alkyl (acyclic or cyclic) or aryl alkyl (acyclic or cyclic) ketone with (R
- Nugent, Thomas C.,Ghosh, Abhijit K.,Wakchaure, Vijay N.,Mohanty, Rashmi R.
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p. 1289 - 1299
(2007/10/03)
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