cas 56210-72-1, (-)-Bis[(S)-1-phenylethyl]amine

Articles about 56210-72-1Total 57 be found

Article title
Article abstract
Author
Journal number and time
Download

An Iridium Catalytic System Compatible with Inorganic and Organic Nitrogen Sources for Dual Asymmetric Reductive Amination Reactions
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
supporting information
p. 27307 - 27311
(2021/11/17)

Method for synthesizing chiral phosphite ligand based on R - 2 - phenylethylamine
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
-
(2021/10/27)

One-Pot Synthesis of Symmetrical Tertiary and Secondary Amines from Carbonyl Compounds, Ammonium Carbonate and Carbon Monoxide as a Reductant
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
supporting information
p. 6557 - 6560
(2019/10/22)

Preparation method of chiral amine compounds
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.
-
Paragraph 0018

(2018/09/13)

B(C6F5)3-Catalyzed Asymmetric Reductive Amination of Ketones with Ammonia Borane
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
p. 11502 - 11509
(2018/09/25)

Hydroboration Catalyzed by 1,2,4,3-Triazaphospholenes
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.
supporting information
p. 5565 - 5568
(2017/10/25)

Iron catalyzed diastereoselective hydrogenation of chiral imines
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
supporting information
p. 5685 - 5688
(2017/07/22)

Catalytic Asymmetric Reductive Condensation of N–H Imines: Synthesis of C2-Symmetric Secondary Amines
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
supporting information
p. 15775 - 15778
(2016/12/16)

Phosphoramidite Ligands Based on Simple 1,2-Diols: Synthesis, Use in Copper-Catalyzed Asymmetric Additions, and Achirotopic Stereogenic Phosphorus Centres
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.
supporting information
p. 2489 - 2496
(2016/08/16)

ORGANOMETALLIC COMPOUND HAVING NITROGEN-CONTAINING HETEROCYCLIC CARBENE LIGAND, CATALYST COMPRISING THE SAME, AND METHOD FOR PRODUCING AMINE COMPOUND
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
-
Paragraph 0165

(2016/10/10)

Design of modified amine transfer reagents allows the synthesis of α-chiral secondary amines via CuH-catalyzed hydroamination
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.
supporting information
p. 9716 - 9721
(2015/08/18)

First efficient two-step/one-pot zirconium (IV)isopropoxide-mediated reductive amination of carbonyl compounds
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
p. 448 - 456
(2015/06/22)

Step-efficient access to chiral primary amines
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.
p. 153 - 166
(2013/02/25)

An investigation of the observed, but counterintuitive, stereoselectivity noted during chiral amine synthesis via N-chiral-ketimines
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.
supporting information
p. 2103 - 2112
(2013/11/19)

Practical synthesis of simplephos ligands: Further development of alkyl-substituted phosphanamines
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
supporting information
p. 6335 - 6343
(2013/10/21)

Metal-free transfer hydrogenation catalysis by B(C6F 5)3
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.
scheme or table
p. 4497 - 4500
(2011/11/04)

Towards energetically viable asymmetric deprotonations: Selectivity at more elevated temperatures with C2-symmetric magnesium bisamides
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.
supporting information; experimental part
p. 2264 - 2266
(2011/04/12)

Sequential reductive amination-hydrogenolysis: A one-pot synthesis of challenging chiral primary amines
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
supporting information; experimental part
p. 2085 - 2092
(2011/10/19)

Transition Metal-Catalyzed C-H Amination Using Unactivated Amines
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.
-
Page/Page column 3; 27

(2011/09/20)

Mild nonepimerizing N -alkylation of amines by alcohols without transition metals
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
supporting information; experimental part
p. 3534 - 3537
(2011/08/10)

Metal-free diastereoselective catalytic hydrogenations of imines using B(C6F5)3
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.
supporting information; experimental part
p. 5729 - 5731
(2011/07/08)

Multialkylation of aqueous ammonia with alcohols catalyzed by water-soluble Cp*Ir-ammine complexes
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
supporting information; experimental part
p. 15108 - 15111
(2010/12/24)

A convenient, highly stereoselective, metal-free synthesis of chiral amines
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
supporting information; experimental part
p. 134 - 136
(2010/07/16)

PROCESS FOR DIASTEREOSELECTIVE CONVERSION OF CHIRAL IMINES
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
-
Page/Page column 15-16

(2010/12/26)

Highly stereoselective metal-free catalytic reduction of Lmines: An easy entry to enantiomerically pure amines and natural And Unnatural α-amino esters
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
supporting information; experimental part
p. 2928 - 2931
(2009/12/05)

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
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
experimental part
p. 1220 - 1223
(2009/12/04)

Selective synthesis of secondary and tertiary amines by Cp*iridium-catalyzed multialkylation of ammonium salts with alcohols
(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
p. 181 - 184
(2008/09/18)

C-H carbene insertion of α-diazo acetamides by photolysis in non-conventional media
(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.
p. 5926 - 5932
(2008/12/21)

(R)-2,2’-Binaphthoyl-(S,S)-di(1-phenylethyl) aminophosphine. Scalable protocols for the syntheses of phosphoramidite (feringa) ligands
-
Smith, Craig R.,Mans, Daniel J.,RajanBabu,Denmark, Scott E.,Nguyen, T.
p. 238 - 247
(2017/09/23)

Mixtures of chiral phosphorous acid diesters and achiral P ligands in the enantio- and diastereoselective hydrogenation of ketimines
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
p. 4523 - 4526
(2008/09/17)

Synthesis and dynamics of atropisomeric (S)-N-(α-phenylethyl)benzamides
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.
p. 12655 - 12664
(2008/03/17)

Asymmetric reductive amination: Convenient access to enantioenriched alkyl-alkyl or aryl-alkyl substituted α-chiral primary amines
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.
p. 1289 - 1299
(2007/10/03)

Asymmetric synthesis of α-monofluoromethyl- and α- difluoromethylbenzylamines through regioselective hydrogenolysis
Asymmetric synthesis of α-monofluoromethyl- and α- difluoromethylbenzylamines through regioselective hydrogenolysis is described. Hydrogenolysis of diastereomerically pure bis(α-methylbenzyl)amine derivatives having partially fluorinated methyl group at b
Kanai, Masatomi,Ueda, Koji,Yasumoto, Manabu,Kuriyama, Yokusu,Inomiya, Kenjin,Ootsuka, Takashi,Katsuhara, Yutaka,Higashiyama, Kimio,Ishii, Akihiro
p. 385 - 391
(2007/10/03)

Enantioselective preparation of β,β-disubstituted α-methylenepropionates by MAO promotion of the zinc schlenk equilibrium
(Chemical Equation Presented) The zinc Schlenk equilibrium, little used since it was first described in 1966, has been promoted through the addition of methylaluminoxane (MAO) to maximize the yield of ZnR2 from deleterious RZnCl by-products. This process allows an SN2′- addition approach to the preparation of chiral β,β-disubstituted α-methylenepropionates with high enantioselectivity (see scheme).
Goldsmith, Paul J.,Teat, Simon J.,Woodward, Simon
p. 2235 - 2237
(2007/10/03)

Stereoselective alkylation of chiral 2-imidoylphenols with organolithium reagents: Synthesis of enantiopure 2-aminoalkylphenols
In this paper the addition of organolithium reagents to chiral imidoylphenols to prepare enantiopure phenolic Mannich-type bases is described. The experimental data show that this kind of imine is surprisingly reactive toward organolithium reagents, differently from classical imines, and does not need any Lewis acid or base activation. Moreover, interesting results have been obtained with aldimines but more unusually with ketimines. This reaction results in high yields and diastereoselectivities and allows the preparation of aminophenols quaternary at the C-1 carbon atom, which cannot be prepared with the methods available till now. The sense of asymmetric induction has been explained and confirmed in agreement with the results previously obtained by hydride reduction of the same substrates. In some cases this procedure is complementary to the reductive one, allowing the preparation of the diastereomers less abundant in the reduction. The reaction allows the synthesis of one or the other of the two diastereomers, choosing the opportune starting imidoylphenol and the organolithium reagent.
Cimarelli, Cristina,Palmieri, Gianni,Volpini, Emanuela
p. 1200 - 1206
(2007/10/03)

The chemical development and scale-up of sampatrilat
The discovery and scale-up of two routes to sampatrilat are described. The first Chemical R and D route used a side product from another development project to accelerate drug supply and expedite the early development programme. The second, more efficient Chemical R and D route had the potential for commercialisation and used an environmentally friendly variant of the Baylis-Hillman reaction, and an asymmetric Michael addition as key steps. Full preparative details for the aminomethacrylate 4, a potentially useful chiral synthon, are given for the first time, along with full experimental details of the asymmetric Michael addition to make the chiral glutarate 5. Finally, a striking polymorph case history is described.
Dunn, Peter J.,Hughes, Michael L.,Searle, Patricia M.,Wood, Albert S.
p. 244 - 253
(2013/09/06)

[PtCL3(C2H4)]-[AmH]+ complexes containing chiral secondary amines: Use as chiral derivatizing agents for the enantiodiscrimination of unsaturated compounds by 195Pt NMR spectroscopy and NMR stereochemical investigation
Ionic complexes [PtCl3(C2H4)]-[AmH]+, containing chiral secondary amines, constitute a versatile class of chiral derivatizing agents (CDAs) for the enantiomeric purity determination of chiral unsaturated compounds via 195Pt NMR spectroscopy. The NMR conformational analysis allows us to search for the stereochemical basis of their enhanced versatility.
Uccello-Barretta,Bernardini,Balzano,Salvadori
p. 123 - 129
(2007/10/03)

Chemoselective reductive amination of aldehydes and ketones by dibutylchlorotin hydride-HMPA complex
Reductive amination of various aldehydes and ketones has been performed effectively by pentacoordinate chloro-substituted tin hydride complex, Bu2SnClH-HMPA. The tin reagent worked particularly well for the case using weakly basic aromatic amines as starting substrates. Stoichiometric amounts of a substrate and a reducing agent were adequate for the reaction. The Sn-Cl bond in the complex plays an important role for both steps of imine formation and subsequent reduction. Highly chemoselective reduction of carbonyls could be achieved regardless of other functionalities such as halogen, carbon- carbon double bond and hydroxyl groups in the starting carbonyls and amines.
Suwa, Toshihiro,Sugiyama, Erika,Shibata, Ikuya,Baba, Akio
p. 789 - 800
(2007/10/03)

Asymmetric reduction of enantiopure imines with zinc borohydride: Stereoselective synthesis of chiral amines
The first application of zinc borohydride in the reduction of enantiopure imines for the stereoselective preparation of both the enantiomers of secondary amines is described. A possible explanation of the stereoselectivity and of the reaction mechanism is
Cimarelli, Cristina,Palmieri, Gianni
p. 2555 - 2563
(2007/10/03)

Asymmetric addition of alkyllithium to chiral imines: α-Naphthylethyl group as a chiral auxiliary
The diastereoselective nucleophilic addition of alkyllithium to N- alkylidene-α-naphthylethylamine was carried out. In the presence of Lewis acids or Lewis bases, organolithiums reacted smoothly with imines to give the corresponding amines in high stereoselectivity (up to 100% de). Furthermore, the resulting optically active amines were found to be useful for asymmetric reactions as chiral ligands.
Yamada, Hideki,Kawate, Tomohiko,Nishida, Atsushi,Nakagawa, Masako
p. 8821 - 8828
(2007/10/03)

Diastereoselective addition of methyllithium and dimethylcuprate-boron trifluoride to imines derived from (S)-1-phenylethylamine
The reactions of dimethylcuprate-boron trifluoride reagents with the imines derived from (S)-1-phenylethylamine afforded the secondary amines by addition to the Si face of the imines. (S,S)-bis(1-phenylethyl)amine and (S)-1-cyclohexylethanamine were prepa
Alvaro, Giuseppe,Savoia, Diego,Valentinetti, Maria R.
p. 12571 - 12586
(2007/10/03)

Asymmetric Synthesis of (1R,1'R)- and (1S,1'S)-Bis(1-arylethyl)amines by way of a Diastereoselective Addition to Chiral Imines and Oxaxolidines with Organometallic Reagents
The asymmetric synthesis of the bis(α-methylbenzyl)amines, (1R,1'R)- and (1S,1'S)-bis(1-arylethyl)amines 6, utilizing a diastereoselective reaction of chiral imines and oxazolidines derived from (R)-phenylglycinol with organometallic reagents, is describe
Higashiyama, Kimio,Inoue, Hiroaki,Yamauchi, Takayasu,Takahashi, Hiroshi
p. 111 - 116
(2007/10/02)

Aminoborohydrides. 6. Diastereoselective Reduction of the Carbon-Nitrogen Double Bond in Chiral Imines Using Lithium Diethylaminoborohydride and Lithium Diisopropylaminoborohydride.
Lithium aminoborohydrides (LAB), obtained by the reaction of n-BuLi with amine-boranes, readily reduce imines to the corresponding secondary amines.Lithium diethylaminoborohydride and lithium diisopropylaminoborohydride reduc
Fuller, Joseph C.,Belisle, Christopher M.,Goralski, Christian T.,Singaram, Bakthan
p. 5389 - 5392
(2007/10/02)

Diastereoselective Nucleophilic Additions to Imines attached to Tricarbonyl(arene)chromium Moieties
A range of imine complexes has been prepared which possess planar chirality associated with the attached tricarbonyl(1,2-disubstituted arene)chromium moiety.Nucleophilic addition to the imine group of these complexes occurs with high diastereoselectivity, providing an efficient route to the asymmetric synthesis of chiral amines.The stereochemical outcome of the additions may be rationalized in terms of a favoured conformer for the complexes, with nucleophilic attack occurring on the face of the imine anti to the sterically demanding Cr(CO)3 group.Related studies have also been carried out on imine complexes in which the chiral auxiliary is instead a carbon centre attached to the imine N atom.In these latter systems high diastereoselectivity was also observed, but was not superior to that achieved with the related free amines.
David, Dorothy M.,Kane-Maguire, Leon A. P.,Pyne, Stephen G.
p. 289 - 296
(2007/10/02)

Diastereoselective hydrogenation and kinetic resolution of imines using rhodium/diphosphine catalyzed hydrogenation
Kinetic resolution of racemic α-methylbenzyl amine can be achieved with 98% e.e. of the remaining amine at 70% conversion using the Rhodium/2S,4S-BDPP catalyzed asymmetric hydrogenation of imines. The same catalyst will hydrogenate optically pure α-methylbenzyl amines with a diastereoselectivity of up to 333:1.
Lensink,De Vries
p. 215 - 222
(2007/10/02)

Diastereoselective Addition of Methylcopper- and Dimethylcuprate-Boron Trifluoride Reagents to (S)-(N-Alkylidene)-1-phenylethylamines
The reactions of methylcopper- and dimethylcuprate-boron trifluoride reagents with aldimines derived from (S)-1-phenylethylamine afford with good diastereoselectivity (S,S)-amines from aromatic imines, but the (R,S)-amine from an aliphatic imine
Boga, Carla,Savoia, Diego,Umani-Ronchi, Achille
p. 291 - 294
(2007/10/02)

Diastereoselectivity of Organometallic Additions to Nitrones Bearing Sterogenic N-Substituents
The diastereoselectivity of organometallic additions to nitrones bearing stereogenic α-arylethyl, β-methoxyalkyl, and β-(silyloxy)alkyl substituents on nitrogen has been investigated.High and complementary diastereoselectivity (90-94percent) was observed in the additions of Grignard reagents to nitrones (e.g. 22 and 23) bearing the potentially chelating β-methoxyalkyl group.However, the opposite selectivity resulted from the reaction of methylmagnesium bromide with the corresponding silyl ether (27).The relative stereochemistry of selected hydroxylamine adducts wasestablished by reduction of their phosphate and carbonate derivatives to known amines (37a,b and 39), by periodate cleavage of a β-hydroxy hydroxylamine (41b), and by various correlations (Scheme II).The high facial diastereoselectivity observed with the N-(β-methoxyalkyl)nitrones is explained by a simple chelation model (Scheme III).
Chang, Zen-Yu,Coates, Robert M.
p. 3464 - 3474
(2007/10/02)

ASYMMETRIC DEPROTONATION OF PROCHIRAL KETONES USING CHIRAL LITHIUM AMIDE BASES
A number of chiral secondary amines have been prepared and used as precursors to the corresponding chiral lithium amide bases.Treatment of either cis-2,6-dimethylcyclohexanone or 4-tert-butylcyclohexanone with a chiral lithium amide, followed by electrophilic quench, gives chiral products in up to 88 percent enantiomeric excess.The results with 4-tert-butylcyclohexanone are in disagreement with an earlier literature report, giving products of lower enantiomeric excess but higher optical rotation.
Cain, Christian M.,Cousins, Richard P. C.,Coumbarides, Greg,Simpkins, Nigel S.
p. 523 - 544
(2007/10/02)

SYNTHESIS OF AMINES BY REDUCTION OF IMINES WITH THE MCl2/NaBH4 (M = Co, Ni) SYSTEM
A simple method for the synthesis of amines by the reduction of imines, anils and enamines, including some chiral substrates, with the MCl2/NaBH4/CH3OH reagent (M = Co, Ni) in 64-82percent yield is described.
Periasamy, M.,Devasagayaraj, A.,Satyanarayana, N.,Narayana, C.
p. 565 - 574
(2007/10/02)

NAD(P)+-NAD(P)H models 70. Reduction of imines with Hantzsch ester in the presence of silica gel
-
Fujii,Aida,Yoshihara,Ohno
p. 3845 - 3847
(2007/10/02)