- Catalytic asymmetric aziridination of enol derivatives in the presence of chiral copper complexes to give optically active α-amino ketones
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A series of acyclic and cyclic enol derivatives 1 has been transformed into the corresponding α-amino-functionalized ketones 2 by means of enantioselective catalytic aziridination with chiral Cu complexes, prepared in situ from [Cu(MeCN)4]PFsu
- Adam, Waldemar,Roschmann, Konrad Johann,Saha-Moeller, Chantu Ranjan
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- Access to Optically Pure Benzosultams by Superelectrophilic Activation
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Through superacid activation, N-(arenesulfonyl)-aminoalcohols derived from readily available ephedrines or amino acids undergo an intramolecular Friedel-Crafts reaction to afford enantiopure benzosultams bearing two adjacent stereocenters in high yields with fully controlled diastereoselectivity. Low-temperature NMR spectroscopy demonstrated the crucial role played by the conformationally restricted chiral dicationic intermediates.
- Michelet, Bastien,Castelli, Ugo,Appert, Emeline,Boucher, Maude,Vitse, Kassandra,Marrot, Jér?me,Guillard, Jér?me,Martin-Mingot, Agnès,Thibaudeau, Sébastien
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supporting information
p. 4944 - 4948
(2020/07/14)
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- Asymmetric Transfer Hydrogenation: Dynamic Kinetic Resolution of α-Amino Ketones
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A series of α-amino ketones were reduced using asymmetric transfer hydrogenation (ATH) through a dynamic kinetic resolution (DKR). The protecting group was matched to the reducing agent, and following optimization, a series of substrates were investigated, giving products in high diastereoselectivity, over 99% ee in several cases and full conversion. The methodology was applied to the enantioselective synthesis of an MDM2-p53 inhibitor precursor.
- Gediya, Shweta K.,Clarkson, Guy J.,Wills, Martin
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p. 11309 - 11330
(2020/10/12)
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- Chiral-Organotin-Catalyzed Kinetic Resolution of Vicinal Amino Alcohols
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A highly efficient kinetic resolution of racemic amino alcohols has been achieved for the first time with a chiral tin catalyst. A chiral organotin compound with 3,4,5-trifluorophenyl groups at the 3,3′-positions of the binaphthyl framework enabled this transformation with excellent yield and high enantioselectivity. The process tolerates aryl- and alkyl-substituted amino alcohols and a variety of other substrates, affording the corresponding products in high enantioselectivity and with s factors up to >500.
- Yang, Hui,Zheng, Wen-Hua
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p. 16177 - 16180
(2019/11/03)
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- METHOD FOR PRODUCING COMPOUND HAVING 1,2-AMINO ALCOHOL SKELETON
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PROBLEM TO BE SOLVED: To provide a method for producing 1,2-amino alcohols that has a high regioselectivity and is safe and efficient. SOLUTION: Provided is a method for producing 1,2-amino alcohols represented by formula 3 below by letting an electrophil
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- Rhodium complex with unsymmetrical vicinal diamine ligand: excellent catalyst for asymmetric transfer hydrogenation of ketones
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New unsymmetrical vicinal diamine ligands with systematic variation in the regio and stereo positions in the amine and sulphonamide groups were synthesized from cheap starting material such as norephedrine. Catalytic Asymmetric Transfer Hydrogenation (ATH) of aromatic alkyl ketones has been investigated using transition metal complexes and new derivatives of monotosylated unsymmetrical vicinal diamine ligands using sodium formate as the hydrogen source, in water and methanol. Chiral secondary alcohols were obtained with excellent enantioselectivity (>95% ee) and conversion of ketones (>95%) with [Rh(Cp)Cl2]2 and ligand 4 as a catalyst. Enantioselectivity was found to be slightly higher with the use of methanol as a solvent for ATH of ketones with sodium formate as the hydrogen source compared to water as a solvent and was found to be consistent with all the ketones investigated. The reaction mixture is homogeneous in methanol unlike in water, where substrate and product are insoluble in water and form separate phase, sodium formate being soluble in water. The activity and enantioselectivity obtained for ATH of ketones using [Rh(Cp)Cl2]2 and unsymmetrical vicinal diamine ligand as catalyst was comparable with the C2 symmetric benchmark ligands like TsDPEN ((1R,2R)-N-(p-tolylsulfonyl)-1,2-diphenylethylene-diamine), and TsCYDN ((1R,2R)-N-(p-tolylsulfonyl)-1,2-cyclohexyl,diamine) under similar reaction conditions. To the best of our knowledge, this is first example of the ATH of ketones with good activity and high enantioselectivity with [Rh(Cp)Cl2]2 and unsymmetrical vicinal diamine ligands as catalyst systems.
- Deshpande, Sudhindra H.,Shende, Vaishali S.,Shingote, Savita K.,Chakravarty, Debamitra,Puranik, Vedavati G.,Chaudhari, Raghunath V.,Kelkar, Ashutosh A.
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p. 51722 - 51729
(2015/06/25)
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- Regiospecific Intermolecular Aminohydroxylation of Olefins by Photoredox Catalysis
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A simple and regiospecific aminohydroxylation of olefins by photoredox catalysis has been developed. N-protected 1-aminopyridinium salts are the key compounds and serve as amidyl radical precursors by the action of Ir photocatalysts, fac-[Ir(ppy)3/s
- Miyazawa, Kazuki,Koike, Takashi,Akita, Munetaka
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supporting information
p. 11677 - 11680
(2015/08/11)
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- Stereoselective geminal difunctionalization of vinyl arenes mediated by the bromonium ion
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An anti-Markovnikov geminal oxyamination of styrenyl alkenes in an intermolecular fashion using the umpolung strategy mediated by the bromonium ion is reported. Isotope labeling studies confirm the migration of the phenyl group in the semipinacol rearrang
- Balaji, Pandur Venkatesan,Chandrasekaran, Srinivasan
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supporting information
p. 70 - 72
(2014/01/06)
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- Remarkable enantioselective α-amination in 1-phenyl-2-(N-alkylamino)- 1-propanol
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(1R,2R)-1-Phenyl-1-alkyl/arylamino-2-(N-alkylamino)propane hydrochloride salts have been synthesized with high degree of enantiomeric purity from (1S,2R)-(+)-1-phenyl-2-(N-alkylamino)-1-propanol through the corresponding chloro derivatives. This reaction sequence involves three inversions with overall inversion of configuration at C-1. Copyright
- Kumar, Borkatte N. Hitesh,Murugesan, Velayutham,Prakasam, Tangirala,Srinivasan, Pathangi S.,Ramana, Devalla V.
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experimental part
p. 262 - 270
(2012/06/01)
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- A facile, one-pot synthesis of Ephedra-based aziridines
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A series of enantiomerically and diastereomerically enriched N-sulfonylaziridines have been prepared by a single-pot process from (1R,2S)- and (1S,2R)-norephedrine and (1S,2S)-pseudonorephedrine. The cyclization process involved N-sulfonylation of the Ephedra alkaloid followed by O-sulfonylation with methanesulfonyl chloride. The bis(sulfonyl)Ephedra derivatives were treated with either hydrazine or sodium hydroxide to afford the N-sulfonylaziridines.
- Groeper, Jonathan A.,Eagles, Joel B.,Hitchcock, Shawn R.
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experimental part
p. 1969 - 1974
(2010/03/03)
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- An annulation reaction for the synthesis of morpholines, thiomorpholines, and piperazines from β-heteroatom amino compounds and vinyl sulfonium salts
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(Chemical Equation Presented) Heterocycling: Diphenyl vinyl sulfonium salt 1 acts first as an electrophile, then a base, and then again as an electrophile in this operationally simple, high yielding, one-pot synthesis of pharmacologically important morpholines, thiomorpholines, and piperazines. Compound 1 is an excellent synthon for the 1,2-ethane dication.
- Yar, Muhammad,McGarrigle, Eoghan M.,Aggarwal, Varinder K.
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p. 3784 - 3786
(2008/12/23)
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- Asymmetric Strecker reaction of N-benzhydrylimines utilising new tropos biphenyldiol-based ligands
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The synthesis of a library of N-arenesulfonyl-1,3-oxazolidinyl-substituted biphenyldiols is presented. A set of two central intermediates together with easily accessible N-arenesulfonylamino alcohols furnish a broad variety of 1,3-oxazolidines. These are applied as chiral tropos ligands in a titanium-mediated Strecker-type reaction of N-benzhydrylimines. A correlation between the ee values in the product and the diastereomeric ratio concerning the chiral axis of the ligand is made. Those substituents in the ligand which proved to lead to a higher preference for one diastereomeric conformer of the chiral axis in related compounds now provide the most selective ligands. Two privileged ligands are identified that afford superior results in 8 of 13 screenings. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Wuennemann, Stefan,Froehlich, Roland,Hoppe, Dieter
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p. 684 - 692
(2008/09/17)
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- Development of a preparative-scale asymmetric synthesis of (R)-p-tolyl methyl sulfoxide for use in a one-pot synthesis of a drug intermediate containing a trifluoromethyl-substituted alcohol functionality
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A one-pot process for the synthesis of (S)-1,1,1-trifluoro-4-(5-fluoro-2- methoxy-phenyl)-4-methyl-2-((A)-toluene-4-sulfinyl-methyl)pentan-2-ol (3) is described, which was a key intermediate for the preparation of a class of novel glucocorticoid receptor ligands. The chemistry features the preparative-scale synthesis of (R)-p-tolyl methyl sulfoxide [(R)-pTMSO] from (2R,4S,5R)-4-methyl- 5-phenyl-3-(tolene-4-sulfonyl)oxathiazolidine-2-oxide (5) and the synthesis of 3 from 5 without isolation of (A)-pTMSO during the process.
- Han, Zhengxu,Song, Jinhua J.,Yee, Nathan K.,Xu, Yibo,Tang, Wenjun,Reeves, Jonathan T.,Tan, Zhulin,Wang, Xiao-Jun,Lu, Bruce,Krishnamurthy, Dhileepkumar,Senanayake, Chris H.
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p. 605 - 608
(2012/12/31)
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- Studies on the reaction of aziridines with nitriles and carbonyls: Synthesis of imidazolines and oxazolidines
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Reaction of N-tosylaziridines with nitriles and carbonyls to produce imidazolines and oxazolidines has been studied in the presence of a variety of Lewis acids. The reaction is efficient with 1 equiv of BF3· Et2O or Et3OBF4 in CH2Cl 2. However, it is catalytic with metal triflates that give the best results for cycloaddition of N-tosylaziridine with nitriles under solvent free conditions. The same reaction with carbonyls proceeds best in CH 2Cl2 in the presence of molecular sieves. Among various triflates, Zn(OTf)2 has been found to be the best. The cleavage of the N-Ts bond of the cyclized products has been studied in order to make it more versatile in synthesis. The mechanistic aspect of the reaction has been studied by using chiral aziridines as substrates. These formal [3 + 2] cycloaddition reactions of aziridines with nitriles and carbonyls proceed in a Ritter fashion.
- Gandhi, Shikha,Bisai, Alakesh,Prasad, B. A. Bhanu,Singh, Vinod K.
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p. 2133 - 2142
(2007/10/03)
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- A new and direct asymmetric synthesis of a hindered chiral amine via a novel sulfinate ketimine derived from N-tosyl-1,2,3-oxathiazolidme-2-oxide: Practical asymmetric synthesis of (R)-sibutramine
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A novel and direct approach for the asymmetric synthesis of (R)-sibutramine via chiral amine 5 using N-tosyl-1,2,3-oxathiazolidine-2-oxide (13) as a recyclable chiral auxiliary is described. Chiral sulfinate imine 16e was obtained by treatment of 13e with
- Han, Zhengxu,Krishnamurthy, Dhileepkumar,Senanayake, Chris H.
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p. 327 - 333
(2012/12/22)
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- Practical and highly stereoselective technology for preparation of enantiopure sulfoxides and sulfinamides utilizing activated and functionally differentiated N-sulfonyl-1,2,3-oxathiazolidine-2-oxide derivatives
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A simple, general, and practical technology to prepare enantiopure 1,2,3-oxathiazolidine-2-oxide derivatives using chiral aryl N-sulfonyl aminoalcohol derivatives and thionyl chloride is reported. The versatility of these novel chiral building blocks (MIOO and TMPOO), was exemplified by the expedient production of a variety of unique chiral sulfoxides and valuable chiral sulfinamides in excellent yields and enantiopurities.
- Han, Zhengxu,Krishnamurthy, Dhileepkumar,Grover, Paul,Fang, Q. Kevin,Su, Xiping,Wilkinson, H. Scott,Lu, Zhi-Hui,Magiera, Daniel,Senanayake, Chris H.
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p. 6386 - 6408
(2007/10/03)
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- A method of manufacturing an amine stereoisomerically
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This invention provides intermediates useful in a method of preparing amine stereoisomers. It also provides a method of preparing sulfoxide and sulfinylamine stereoisomers using certain of the intermediates.
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Page/Page column 53-55
(2010/02/12)
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- Synthesis of chiral oxazolidin-2-ones by 1,2-amino alcohols, carbon dioxide and electrogenerated acetonitrile anion
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An improved electrochemical synthesis of chiral oxazolidin-2-ones from chiral 1,2-amino alcohols is obtained by direct electrolysis of solutions of MeCN-TEAP containing the amino alcohol, with subsequent CO2 bubbling and addition of TsCl. This
- Feroci, Marta,Gennaro, Armando,Inesi, Achille,Orsini, Monica,Palombi, Laura
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p. 5863 - 5865
(2007/10/03)
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- Enantioselective synthesis of optically active homoallylamines by nucleophilic addition of chirally modified allylboranes to N-silylimines
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Enantioselectivity in the allylboration of W-silylimines with a variety of chirally modified allylboron reagents has been examined. Optically active N-sulfonylarhino alcohols (16,17 and 19) derived from D-camphor and norephedrine were found to be efficient chiral ligands for the allylboration reagent. These reagents smoothly reacted with Ar-silylimines to give the corresponding homoallylic amines in a high level of enantioselectivity up to 96% ee.
- Itsuno, Shinichi,Watanabe, Katsuhiro,Matsumoto, Takeshi,Kuroda, Shizuc,Yokoi, Ayako,El-Shehawy, Ashraf
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p. 2011 - 2016
(2007/10/03)
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- Chlorination reactions of ephedrines revisited. Stereochemistry and functional groups effect on the reaction mechanisms
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The stereochemistry of the chlorination reactions with SOCl2 of free ephedrine and pseudoephedrine and their hydrochlorides, examides and sulfonamides was analyzed. Chlorination of free and hydrochloride erythro isomers occurs with 100% inversion of configuration at C-1 (S(N)2 mechanism). Chlorination of examides and sulfonamides of erythro isomers occurs with retention of the configuration at C-1, (S(N)i mechanism). Chlorination reactions in all three isomers and derivatives hydrochlorides, examides or sulfonamides gave the same ratio of erythro (40%) and three isomers (60%) (S(N)1 mechanism). Treatment of the isomeric mixture of the chlorodeoxyephedrine and chlorodeoxypseudoephedrine hydrochloride in DMSO with HCl changes the isomeric ratio, increasing the erythro isomer content (65%). Using the erythro ethanolamines it is possible to arrive stereoselectively at the erythro chloroamines if the compound is previously tosylated or converted to the amide, or to the three chloroamines if the compound is directly chlorinated with SOCl2.
- Flores-Parra, Angelina,Suarez-Moreno, Patricia,Sanchez-Ruiz, Sonia A.,Tlahuextl, Margarita,Jaen-Gaspar, Javier,Tlahuext, Hugo,Salas-Coronado, Raul,Cruz, Alejandro,Noeth, Heinrich,Contreras, Rosalinda
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p. 1661 - 1671
(2007/10/03)
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- Asymmetric synthesis of butenolide and butyrolactone derivatives
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2-Trimethylsiloxyfuran and 4-methoxy-2-trimethylsiloxyfuran, which are readily prepared from butenolide and methyl tetronate respectively, have been reacted with a series of homochiral ortho-esters and oxazolidine derivatives in the presence of Lewis acids to afford homochiral 2(5H)-furanone derivatives. The structures of three products have been determined using nmr spectroscopy and, where possible, by X-ray analysis. Preliminary experiments have been carried out involving conjugate addition to these unsaturated lactones, demonstrating their potential as substrates for natural product synthesis.
- Pelter,Ward,Sirit
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p. 1745 - 1762
(2007/10/02)
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- Stereoselective Aldol Reactions. Reaction of Chiral Ester Titanium Enolate with Aldehydes
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The chiral ester 1 was enolized under TiCl4/Et3N conditions and reacted with aldehydes to give moderate to good stereoselectivities.The chiral auxiliary group can be removed by simple saponification and recovered.
- Xiang, YiBin,Olivier , Eric,Ouimet, Nathalie
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p. 457 - 460
(2007/10/02)
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- Kinetic resolution of dl-2,3-epoxy alcohols using chiral titanium complex with amino alcohol derived ligand
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Highly effective kinetic resolution of primary dl-223-epoxy alcohols such as 2,3-epoxygeraniol and 2,3-epoxynerol was realized by using a combination of Ti(OiPr)4 and (1R,2S)-2-(p-toluenesulfonylamino)-1-(2,4,6-trimethylphenyl)-1-propanol as a chiral Lewis acid catalyst.
- Ishikawa, Akira,Katsuki, Tsutomu
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p. 3547 - 3550
(2007/10/02)
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- Diastereoselective synthesis of enantiomerically pure 3-organosulfonyl-2-(2-oxocycloalkyl)-1,3-oxazolidines from 2-formylcycloalkanones and β-aminoalkanols
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The title compounds (3-arylsulfonyl- or 3-mesyl-2-(2-oxocycloalkyl)-1,3-oxazolidines) belonging to two different diastereomeric series, are prepared selectively by variation of the condensation conditions. By this, the chiral information of the 2-amino-1-
- Hoppe,Hoffmann,Gartner,Krettek,Hoppe
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p. 1157 - 1162
(2007/10/02)
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- STEREOCONVERGENT CROTYLSTANNANE ADDITION TO NOR-EPHEDRINE-DERIVED 2-METHOXY OXAZOLIDINES. A CLUE TOWARDS A SYNCLINAL TRANSITION STATE GEOMETRY
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The Lewis acid promoted addition of crotyl-n-tributylstannane to a nor-ephedrine-derived 2-methoxy-oxazolidine has been studied.This stereoconvergent reaction allows highly selective C-C bond formation and takes place with opposite stereochemistry with respect to the analogous silylketenethioacetal addition.This result suggests a preference for a synclinal transition state geometry.
- Pasquarello, A.,Poli, G.,Potenza, D.,Scolastico, C.
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p. 429 - 432
(2007/10/02)
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- Remarkable difference of chemoselectivity in the reduction of α-bromo ketones with dibutyltin dihydride system
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Remarkably different chemoselectivities were noted in the reduction of α-bromo ketones by n-Bu2SnH2 system. Without additive, the reduction of α-bromo group took place. While, the addition of small amounts of p-Dinitrobenzene (DNB) caused the chemoselective reduction of carbonyl group.
- Shibata, Ikuya,Nakamura, Kenji,Baba, Akio,Matsuda, Haruo
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p. 6381 - 6384
(2007/10/02)
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- ASYMMETRIC SYNTHESIS OF 3,4-CIS-SUBSTITUTED β-LACTAMS VIA CHIRAL NOREPHEDRINE-DERIVED OXAZOLIDINES.
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A diastereo- and enantioselective approach to functionalized 3,4-cis-β-lactams 9 and 16 was developed based on the use of chiral norephedrine-derived oxazolidines.The key-steps in the synthesis of 9 (Scheme 1) are the potassium hypochlorite epoxidation of
- Cardani, S.,Gennari, C.,Scolastico, C.,Villa, R.
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p. 7397 - 7404
(2007/10/02)
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- ENANTIOSELECTIVE ADDITION OF CHIRALLY MODIFIED METHYLTITANIUM REAGENTS TO AROMATIC ALDEHYDES
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N-Sulfonylated derivatives of norephedrine are excellent ligands for chirally modified methyltitanium reagents, the latter reacting enantioselectively with aromatic aldehydes (ee ca. 90percent) to form R-cunfigurated carbinols.
- Reetz, M. T.,Kuekenhoehner, T.,Weinig, P.
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p. 5711 - 5714
(2007/10/02)
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