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Janine Cossy - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of Optically Active α‑Trifluoromethylamines by Rearrangement of β‑Amino-α-trifluoromethyl Alcohols
2018Co-Authors: Zeina Neouchy, Domingo Gomez Pardo, Janine CossyAbstract:The synthesis of various optically active α-trifluoromethylamines has been realized from β-amino-α-trifluoromethyl alcohols via an Aziridinium ion intermediate under kinetic conditions
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ring contraction of 3 hydroxy 3 trifluoromethyl piperidines synthesis of 2 substituted 2 trifluoromethyl pyrrolidines
ChemInform, 2016Co-Authors: Alexandra Feraldixypolia, Domingo Gomez Pardo, Janine CossyAbstract:The key step for the synthesis of the title pyrrolidines is the Tf2O-induced ring contraction of piperidine (I) leading to the key Aziridinium intermediate which is regioselectively opened by different nucleophiles, such as alcohols, amines, thiols, carbanions, or halides.
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stereoselective rearrangement of trifluoromethyl prolinols to enantioenriched 3 substituted 2 trifluoromethyl piperidines
ChemInform, 2015Co-Authors: Sarah Rioton, Aurelie Orliac, Zeina Antoun, Roselyne Bidault, Domingo Gomez Pardo, Janine CossyAbstract:The straightforward regio- and diastereoselective title reaction allows for the synthesis of a broad range of 3-substituted 2-(trifluoromethyl)piperidines which are formed via ring-opening of a (trifluoromethyl)Aziridinium intermediate by various electrophiles including iodine, secondary amines, aniline, alcohols and thiols, sodium phenolate and water as well as C-anions such as cyanide.
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ring contraction of 3 hydroxy 3 trifluoromethyl piperidines synthesis of 2 substituted 2 trifluoromethyl pyrrolidines
Chemistry: A European Journal, 2015Co-Authors: Alexandra Feraldixypolia, Domingo Gomez Pardo, Janine CossyAbstract:A ring contraction of 3-hydroxy-3-(trifluoromethyl)piperidines was achieved via an Aziridinium intermediate. This contraction facilitates the synthesis of a series of 2-substituted 2-(trifluoromethyl)pyrrolidines incorporating a quaternary center at the C2 position.
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stereoselective rearrangement of trifluoromethyl prolinols to enantioenriched 3 substituted 2 trifluoromethyl piperidines
Organic Letters, 2015Co-Authors: Sarah Rioton, Aurelie Orliac, Zeina Antoun, Roselyne Bidault, Domingo Gomez Pardo, Janine CossyAbstract:3-Substituted 2-(trifluoromethyl)piperidines B were synthesized by ring expansion of (trifluoromethyl)prolinols A, which were obtained from l-proline via an Aziridinium intermediate C. The ring opening of the (trifluoromethyl)Aziridinium intermediate by different nucleophiles is regio- and diastereoselective.
Domingo Gomez Pardo - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of Optically Active α‑Trifluoromethylamines by Rearrangement of β‑Amino-α-trifluoromethyl Alcohols
2018Co-Authors: Zeina Neouchy, Domingo Gomez Pardo, Janine CossyAbstract:The synthesis of various optically active α-trifluoromethylamines has been realized from β-amino-α-trifluoromethyl alcohols via an Aziridinium ion intermediate under kinetic conditions
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ring contraction of 3 hydroxy 3 trifluoromethyl piperidines synthesis of 2 substituted 2 trifluoromethyl pyrrolidines
ChemInform, 2016Co-Authors: Alexandra Feraldixypolia, Domingo Gomez Pardo, Janine CossyAbstract:The key step for the synthesis of the title pyrrolidines is the Tf2O-induced ring contraction of piperidine (I) leading to the key Aziridinium intermediate which is regioselectively opened by different nucleophiles, such as alcohols, amines, thiols, carbanions, or halides.
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stereoselective rearrangement of trifluoromethyl prolinols to enantioenriched 3 substituted 2 trifluoromethyl piperidines
ChemInform, 2015Co-Authors: Sarah Rioton, Aurelie Orliac, Zeina Antoun, Roselyne Bidault, Domingo Gomez Pardo, Janine CossyAbstract:The straightforward regio- and diastereoselective title reaction allows for the synthesis of a broad range of 3-substituted 2-(trifluoromethyl)piperidines which are formed via ring-opening of a (trifluoromethyl)Aziridinium intermediate by various electrophiles including iodine, secondary amines, aniline, alcohols and thiols, sodium phenolate and water as well as C-anions such as cyanide.
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ring contraction of 3 hydroxy 3 trifluoromethyl piperidines synthesis of 2 substituted 2 trifluoromethyl pyrrolidines
Chemistry: A European Journal, 2015Co-Authors: Alexandra Feraldixypolia, Domingo Gomez Pardo, Janine CossyAbstract:A ring contraction of 3-hydroxy-3-(trifluoromethyl)piperidines was achieved via an Aziridinium intermediate. This contraction facilitates the synthesis of a series of 2-substituted 2-(trifluoromethyl)pyrrolidines incorporating a quaternary center at the C2 position.
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stereoselective rearrangement of trifluoromethyl prolinols to enantioenriched 3 substituted 2 trifluoromethyl piperidines
Organic Letters, 2015Co-Authors: Sarah Rioton, Aurelie Orliac, Zeina Antoun, Roselyne Bidault, Domingo Gomez Pardo, Janine CossyAbstract:3-Substituted 2-(trifluoromethyl)piperidines B were synthesized by ring expansion of (trifluoromethyl)prolinols A, which were obtained from l-proline via an Aziridinium intermediate C. The ring opening of the (trifluoromethyl)Aziridinium intermediate by different nucleophiles is regio- and diastereoselective.
Norbert De Kimpe - One of the best experts on this subject based on the ideXlab platform.
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nucleophile dependent regio and stereoselective ring opening of 1 azoniabicyclo 3 1 0 hexane tosylate
ChemInform, 2015Co-Authors: Mikyung Ji, Hannelore Goossens, Dietmar Hertsen, Norbert De Kimpe, Michel Waroquier, Matthias Dhooghe, Dooha Yoon, Veronique Van Speybroeck, Hyunjoon HaAbstract:The title tosylate (III), a stable bicyclic Aziridinium salt, is synthesized and subjected to ring-opening reactions with various nucleophiles including halides, azide, acetate, and cyanide.
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Reactivity of Aziridinium Salts in Different Solvents Unraveled by a Combined Theoretical and Experimental Approach
Topics in Heterocyclic Chemistry, 2014Co-Authors: Hannelore Goossens, Dietmar Hertsen, Karen Mollet, Saron Catak, Matthias D'hooghe, Frank De Proft, Paul Geerlings, Norbert De Kimpe, Michel Waroquier, Veronique Van SpeybroeckAbstract:This chapter focuses on the importance of Aziridinium ions as intermediates in organic chemistry. The principal aim is to gain insight into the factors to take into account for the selective synthesis of a variety of functionalized amines via Aziridinium salts, such as the nature of the Aziridinium ion (ring strain and N- and C-substituents of the aziridine ring), the nucleophile, and the solvent environment. Molecular modeling is used to investigate kinetics, electrostatics, and frontier molecular orbitals of reactions involving intermediate Aziridinium ions, such as the nucleophilic ring opening of aziridines, the ring expansion of nitrogen heterocycles, and the ene reactions with triazolinedione. Open image in new window
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nucleophile dependent regio and stereoselective ring opening of 1 azoniabicyclo 3 1 0 hexane tosylate
Chemistry-an Asian Journal, 2014Co-Authors: Mikyung Ji, Hannelore Goossens, Dietmar Hertsen, Norbert De Kimpe, Michel Waroquier, Matthias Dhooghe, Dooha Yoon, Veronique Van Speybroeck, Hyunjoon HaAbstract:1-[(1R)-(1-Phenylethyl)]-1-azoniabicyclo[3.1.0]hexane tosylate was generated as a stable bicyclic Aziridinium salt from the corresponding 2-(3-hydroxypropyl)aziridine upon reaction with p-toluenesulfonyl anhydride. This bicyclic Aziridinium ion was then treated with various nucleophiles including halides, azide, acetate, and cyanide in CH3CN to afford either piperidines or pyrrolidines through regio- and stereoselective ring opening, mediated by the characteristics of the applied nucleophile. On the basis of DFT calculations, ring-opening reactions under thermodynamic control yield piperidines, whereas reactions under kinetic control can yield both piperidines and pyrrolidines depending on the activation energies for both pathways.
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regioselectivity in the ring opening of non activated aziridines
ChemInform, 2012Co-Authors: Sonja Stankovic, Saron Catak, Michel Waroquier, Veronique Van Speybroeck, Matthias Dhooghe, Heesung Eum, Norbert De KimpeAbstract:In this critical review, the ring opening of non-activated 2-substituted aziridinesvia intermediate Aziridinium salts will be dealt with. Emphasis will be put on the relationship between the observed regioselectivity and inherent structural features such as the nature of the C2 aziridine substituent and the nature of the electrophile and the nucleophile. This overview should allow chemists to gain insight into the factors governing the regioselectivity in Aziridinium ring openings (81 references).
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systematic study of halide induced ring opening of 2 substituted Aziridinium salts and theoretical rationalization of the reaction pathways
European Journal of Organic Chemistry, 2010Co-Authors: Matthias Dhooghe, Saron Catak, Michel Waroquier, Veronique Van Speybroeck, Sonja Stankovic, Yongeun Kim, Norbert De KimpeAbstract:The ring-opening reactions of 2-alkyl-substituted 1,1-bis(arylmethyl)- and 1-methyl-1-(1-phenylethyl)Aziridinium salts with fluoride, chloride, bromide and iodide in acetonitrile have been evaluated for the first time in a systematic way. The reactions with fluoride afforded regioisomeric mixtures of primary and secondary fluorides, whereas secondary β-chloro, β-bromo and β-iodo amines were obtained as the sole reaction products from the corresponding halides by regiospecific ring opening at the substituted position. Both experimental and computational results revealed that the reaction outcomes in the cases of chloride, bromide and iodide were dictated by product stability through thermodynamic control involving rearrangement of the initially formed primary halides to the more stable secondary halides. The ring opening of the same Aziridinium salts with fluoride, however, was shown to be mediated by steric interactions (kinetic control), with the corresponding primary β-fluoro amines being obtained as the main reaction products. Only for 2-acylAziridinium ions was the reaction outcome shown to be under full substrate control, affording secondary β-fluoro, β-chloro, β-bromo and β-iodo amines through exclusive attack at the activated α-carbonyl carbon atom.
Hyunsoon Chong - One of the best experts on this subject based on the ideXlab platform.
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Synthetic and theoretical investigation on the one-pot halogenation of β-amino alcohols and nucleophilic ring opening of Aziridinium ions.
Organic & biomolecular chemistry, 2015Co-Authors: Yunwei Chen, Xiang Sun, Shengnan Jin, Yongliang Zhong, Zirui Liu, Andrey Rogachev, Hyunsoon ChongAbstract:Aziridinium ions are useful reactive intermediates for the synthesis of enantiomerically enriched building blocks. However, N,N-dialkyl Aziridinium ions are relatively underutilized in the synthesis of optically active molecules as compared to other three-membered ring cogeners, aziridines and epoxides. The characterization of both optically active Aziridinium ions and secondary β-halo amines as the precursor molecules of Aziridinium ions has been scarcely reported and is often unclear. In this paper, we report for the first time the preparation and experimental and theoretical characterization of optically active Aziridinium ions and secondary β-halo amines. Optically active secondary N,N-substituted β-halo amines were efficiently synthesized from N,N-substituted alaninol via formation and ring opening at the more hindered carbon of Aziridinium ions by halides. Optically active β-halo amines and Aziridinium ions were characterized by NMR and computational analyses. The structure of an optically active β-chloro amine was confirmed via X-ray crystallographic analysis. The Aziridinium ions derived from N,N-dibenzyl alaniol remained stable only for several hours, which was long enough for analyses of NMR and optical activity. The stereospecific ring opening of Aziridinium ions by halides was computationally studied using DFT and highly-accurate DLPNO-CCSD(T) methods. The highly regioselective and stereoselective ring opening of Aziridinium ions was applied for efficient one-pot conversion of β-alaninols to enantiomerically enriched β-amino alcohols, β-amino nitriles, and vicinal diamine derivatives.
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Synthesis, characterization, and nucleophilic ring opening reactions of cyclohexyl-substituted β-haloamines and Aziridinium ions
Tetrahedron Letters, 2015Co-Authors: Hyunsoon Chong, Xiang Sun, Yunwei Chen, Meng WangAbstract:Abstract Cyclohexyl-substituted β-haloamines and Aziridinium ions were prepared and characterized. Stereospecific ring opening of Aziridinium ions was applied for efficient synthesis of vicinal amine, β-amino acid, and tetrahydroisoquinoline (THIQ) analogues. Nucleophilic ring opening reactions of Aziridinium ions and N-protected aziridine analogues were for the first time comparatively studied. The result of nucleophilic reactions clearly indicates that Aziridinium ions were significantly more reactive toward nucleophilic ring opening than the aziridine analogues.
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Application of Aziridinium ring opening for preparation of optically active diamine and triamine analogues: highly efficient synthesis and evaluation of DTPA-based MRI contrast enhancement agents
RSC advances, 2015Co-Authors: Xiang Sun, Hyun A Song, Chi Soo Kang, Yunwei Chen, Shengnan Jin, Henry Bryant, Joseph A. Frank, Hyunsoon ChongAbstract:Ring opening of Aziridinium ions with nitrogen nucleophiles was applied to the highly efficient synthesis of optically active vicinal diamines and diethylene triamine pentaacetic acid (DTPA) analogues as potential magnetic resonance imaging (MRI) contrast enhancement agents. The synthetic method features a column-free isolation of the regiospecific and stereospecific nucleophilic substitution products of enantiomerically enriched Aziridinium ions in excellent yield.
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Stereoselective and regioselective intramolecular Friedel-Crafts reaction of Aziridinium ions for synthesis of 4-substituted tetrahydroisoquinolines.
Organic letters, 2013Co-Authors: Hyunsoon Chong, Yunwei ChenAbstract:Optically active 4-substituted tetrahydroisoquinolines were synthesized via intramolecular Friedel-Crafts (FC) reactions of Aziridinium ions in a highly regio- and stereoselective manner. Control experiments suggest the formation and ring-opening of Aziridinium ions as the key intermediates in the Lewis acid catalyzed FC reactions.
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a highly effective bifunctional ligand for radioimmunotherapy applications
Chemical Communications, 2011Co-Authors: Hyunsoon Chong, Hyun A Song, Chi Soo Kang, Xiang Sun, Mamta Dadwal, Hyunbeom Lee, Xiaoli Lan, Yunwei Chen, Anzhi DaiAbstract:A novel bifunctional ligand (3p-C-NETA) for antibody-targeted radioimmunotherapy (RIT) of β-emitting radioisotopes 90Y and 177Lu was efficiently synthesized via an unexpected regiospecific ring opening of an Aziridinium ion. 3p-C-NETA instantly formed a very stable complex with 90Y or 177Lu. 3p-C-NETA is an excellent bifunctional ligand for RIT.
Matthias Dhooghe - One of the best experts on this subject based on the ideXlab platform.
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nucleophile dependent regio and stereoselective ring opening of 1 azoniabicyclo 3 1 0 hexane tosylate
ChemInform, 2015Co-Authors: Mikyung Ji, Hannelore Goossens, Dietmar Hertsen, Norbert De Kimpe, Michel Waroquier, Matthias Dhooghe, Dooha Yoon, Veronique Van Speybroeck, Hyunjoon HaAbstract:The title tosylate (III), a stable bicyclic Aziridinium salt, is synthesized and subjected to ring-opening reactions with various nucleophiles including halides, azide, acetate, and cyanide.
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nucleophile dependent regio and stereoselective ring opening of 1 azoniabicyclo 3 1 0 hexane tosylate
Chemistry-an Asian Journal, 2014Co-Authors: Mikyung Ji, Hannelore Goossens, Dietmar Hertsen, Norbert De Kimpe, Michel Waroquier, Matthias Dhooghe, Dooha Yoon, Veronique Van Speybroeck, Hyunjoon HaAbstract:1-[(1R)-(1-Phenylethyl)]-1-azoniabicyclo[3.1.0]hexane tosylate was generated as a stable bicyclic Aziridinium salt from the corresponding 2-(3-hydroxypropyl)aziridine upon reaction with p-toluenesulfonyl anhydride. This bicyclic Aziridinium ion was then treated with various nucleophiles including halides, azide, acetate, and cyanide in CH3CN to afford either piperidines or pyrrolidines through regio- and stereoselective ring opening, mediated by the characteristics of the applied nucleophile. On the basis of DFT calculations, ring-opening reactions under thermodynamic control yield piperidines, whereas reactions under kinetic control can yield both piperidines and pyrrolidines depending on the activation energies for both pathways.
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regioselectivity in the ring opening of non activated aziridines
ChemInform, 2012Co-Authors: Sonja Stankovic, Saron Catak, Michel Waroquier, Veronique Van Speybroeck, Matthias Dhooghe, Heesung Eum, Norbert De KimpeAbstract:In this critical review, the ring opening of non-activated 2-substituted aziridinesvia intermediate Aziridinium salts will be dealt with. Emphasis will be put on the relationship between the observed regioselectivity and inherent structural features such as the nature of the C2 aziridine substituent and the nature of the electrophile and the nucleophile. This overview should allow chemists to gain insight into the factors governing the regioselectivity in Aziridinium ring openings (81 references).
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systematic study of halide induced ring opening of 2 substituted Aziridinium salts and theoretical rationalization of the reaction pathways
European Journal of Organic Chemistry, 2010Co-Authors: Matthias Dhooghe, Saron Catak, Michel Waroquier, Veronique Van Speybroeck, Sonja Stankovic, Yongeun Kim, Norbert De KimpeAbstract:The ring-opening reactions of 2-alkyl-substituted 1,1-bis(arylmethyl)- and 1-methyl-1-(1-phenylethyl)Aziridinium salts with fluoride, chloride, bromide and iodide in acetonitrile have been evaluated for the first time in a systematic way. The reactions with fluoride afforded regioisomeric mixtures of primary and secondary fluorides, whereas secondary β-chloro, β-bromo and β-iodo amines were obtained as the sole reaction products from the corresponding halides by regiospecific ring opening at the substituted position. Both experimental and computational results revealed that the reaction outcomes in the cases of chloride, bromide and iodide were dictated by product stability through thermodynamic control involving rearrangement of the initially formed primary halides to the more stable secondary halides. The ring opening of the same Aziridinium salts with fluoride, however, was shown to be mediated by steric interactions (kinetic control), with the corresponding primary β-fluoro amines being obtained as the main reaction products. Only for 2-acylAziridinium ions was the reaction outcome shown to be under full substrate control, affording secondary β-fluoro, β-chloro, β-bromo and β-iodo amines through exclusive attack at the activated α-carbonyl carbon atom.
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regio and stereospecific ring opening of 1 1 dialkyl 2 aryloxymethyl Aziridinium salts by bromide
ChemInform, 2006Co-Authors: Matthias Dhooghe, Veronique Van Speybroeck, Michel Waroquier, Norbert De KimpeAbstract:Enantiomerically pure 2-(aryloxymethyl)aziridines are efficiently transformed into chiral N-(2-bromo-3-aryloxypropyl)amines via a regio- and stereospecific ring opening of the intermediate Aziridinium salts, and the experimental results are rationalized on the basis of some high level ab initio calculations.