The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Jia-rong Chen - One of the best experts on this subject based on the ideXlab platform.
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Visible-Light-Driven Nitrogen Radical-Catalyzed [3 + 2] Cyclization of Vinylcyclopropanes and N-Tosyl Vinylaziridines with Alkenes.
Organic letters, 2020Co-Authors: Quan-qing Zhao, Xue‐song Zhou, Wen-jing Xiao, Jia-rong ChenAbstract:A visible light photoredox-promoted and nitrogen radical catalyzed [3 + 2] cyclization of vinylcyclopropanes and N-tosyl Vinylaziridines with alkenes is developed. Key to the success of this proces...
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visible light driven nitrogen radical catalyzed 3 2 cyclization of vinylcyclopropanes and n tosyl Vinylaziridines with alkenes
Organic Letters, 2020Co-Authors: Quan-qing Zhao, Wen-jing Xiao, Xuesong Zhou, Jia-rong ChenAbstract:A visible light photoredox-promoted and nitrogen radical catalyzed [3 + 2] cyclization of vinylcyclopropanes and N-tosyl Vinylaziridines with alkenes is developed. Key to the success of this proces...
Toshiro Ibuka - One of the best experts on this subject based on the ideXlab platform.
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asymmetric synthesis of β2 3 amino acids by ini pd 0 promoted metalation and addition of chiral 2 Vinylaziridines
Tetrahedron, 2002Co-Authors: Miyuki Anzai, Hiroaki Ohno, Nobutaka Fujii, Toshiro Ibuka, Reiko Yanada, Yoshiji TakemotoAbstract:Abstract The reaction of optically active 3-alkyl-2-Vinylaziridines with various aldehydes in the presence of InI and Pd(PPh 3 ) 4 gives rise to chiral syn , syn -2-vinyl-1,3-amino alcohols possessing three contiguous chiral centers stereoselectively. The ratio of the syn , syn -isomer to the other three isomers is significantly affected by the C3-substituents of aziridines as well as the alkyl groups of aldehydes. In addition, the obtained 1,3-aminoalcohols can be converted into biologically important β 2,3 -amino acid derivatives.
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Asymmetric synthesis of β2,3-amino acids by InI–Pd(0)-promoted metalation and addition of chiral 2-Vinylaziridines
Tetrahedron, 2002Co-Authors: Miyuki Anzai, Hiroaki Ohno, Nobutaka Fujii, Toshiro Ibuka, Reiko Yanada, Yoshiji TakemotoAbstract:Abstract The reaction of optically active 3-alkyl-2-Vinylaziridines with various aldehydes in the presence of InI and Pd(PPh 3 ) 4 gives rise to chiral syn , syn -2-vinyl-1,3-amino alcohols possessing three contiguous chiral centers stereoselectively. The ratio of the syn , syn -isomer to the other three isomers is significantly affected by the C3-substituents of aziridines as well as the alkyl groups of aldehydes. In addition, the obtained 1,3-aminoalcohols can be converted into biologically important β 2,3 -amino acid derivatives.
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stereoselective synthesis of nonracemic 1 3 amino alcohols from chiral 2 Vinylaziridines by ini pd 0 promoted metalation
Tetrahedron Letters, 2001Co-Authors: Yoshiji Takemoto, Hiroaki Ohno, Nobutaka Fujii, Miyuki Anzai, Reiko Yanada, Toshiro IbukaAbstract:Abstract Treatment of optically active 3-alkyl-2-Vinylaziridines 1 , 8 and 9 and allylic acetates 10 and 11 with InI in the presence of Pd(PPh 3 ) 4 gives rise to chiral allylindiums bearing an amino group at the δ-position, which react with several aldehydes in highly regio- and stereoselective manner to afford the syn , syn -2-vinyl-1,3-amino alcohols 2a , 5a – 7a and 12a – 14a possessing three contiguous chiral centers in good yields.
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Stereoselective synthesis of nonracemic 1,3-amino alcohols from chiral 2-Vinylaziridines by InI–Pd(0)-promoted metalation
Tetrahedron Letters, 2001Co-Authors: Yoshiji Takemoto, Hiroaki Ohno, Nobutaka Fujii, Miyuki Anzai, Reiko Yanada, Toshiro IbukaAbstract:Abstract Treatment of optically active 3-alkyl-2-Vinylaziridines 1 , 8 and 9 and allylic acetates 10 and 11 with InI in the presence of Pd(PPh 3 ) 4 gives rise to chiral allylindiums bearing an amino group at the δ-position, which react with several aldehydes in highly regio- and stereoselective manner to afford the syn , syn -2-vinyl-1,3-amino alcohols 2a , 5a – 7a and 12a – 14a possessing three contiguous chiral centers in good yields.
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Selective synthesis of cis-2-vinyl-3-alkylaziridines and 3-pyrrolines from common intermediates (Z)-4-N-arylsulfonylaminoalk-2-en-1-ols
Journal of the Chemical Society Perkin Transactions 1, 1999Co-Authors: Kiyonori Ishii, Hiroaki Ohno, Nobutaka Fujii, Yoshiji Takemoto, Eriko Osawa, Yumiko Yamaoka, Toshiro IbukaAbstract:A simple method for the synthesis of both cis-2-Vinylaziridines and 3-pyrrolines from common intermediate (Z)-4-(N-arylsulfonyl)amino-4-alkylbut-2-en-1-ols, is described. Palladium(0)-catalyzed reactions of methyl carbonates of the N-protected (Z)-4-amino-4-alkylbut-2-en-1-ols yield predominantly cis-3-alkyl-2-Vinylaziridines. Alternatively, upon exposure to sodium hydride, methanesulfonates derived from N-protected (Z)-4-amino-4-alkylbut-2-en-1-ols give exclusively the corresponding 3-pyrrolines in high yields. A synthesis of biologically important (S)-3,4-dehydroproline is also presented.
Peter Somfai - One of the best experts on this subject based on the ideXlab platform.
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Investigations of the [2,3]-Sigmatropic Rearrangements of Vinylaziridines and Allylic Amines
Synlett, 2007Co-Authors: Peter Somfai, Olaf PankninAbstract:This account summarizes our studies of [2,3]-sigmatropic rearrangements of Vinylaziridines and allylic amines. The scope and limitations of the reactions as well as our present mechanistic understanding are also discussed.
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A Regio- and Stereodivergent Route to All Isomers of vic-Amino Alcohols.
ChemInform, 2003Co-Authors: Berit Olofsson, Peter SomfaiAbstract:The first part of this thesis describes a synthetic strategythat provides all eight possible isomers of a given vic-aminoalcohol starting from vinylepoxides. The value of a generalroute is evident, as several isomers are needed ininvestigations of structure-activity relationships forpharmacologically active derivatives, and for optimizing theperformance of chiral ligands containing the amino alcoholmoiety. Vinylepoxides, obtained in high enantiomeric excess, werering-opened both with inversion and retention ofstereochemistry, delivering two diastereomeric amino alcoholswith high regio- and stereoselectivity. Via ring-closure toaziridines and subsequent regioselective ring-opening withsuitable oxygen nucleophiles, the two remaining amino alcoholswere selectively achieved. Within this study, two efficient protocols for theregioselective and stereospecific aminolysis of vinylepoxideshave been presented. Comparedto previous methods, theseprocedures use milder reaction conditions, shorter reactiontimes, generally give higher yields and are applicable to alarger set of substrates. Furthermore, the ring-closure ofvic-amino alcohols to the corresponding N-H Vinylaziridines hasbeen investigated. Three routes have been found useful, whichone is preferred depends on substrate and scale. In the second part of the thesis, the synthetic strategy isapplied on the synthesis of Sphingosine and its regio- andstereoisomers. Moreover, a rapid way of determining relativeconfiguration of vic-amino alcohols is described, which shouldbe of substantial use when amino alcohols are formed bydiastereoselective reactions. amino alcohols, vinylepoxides, Vinylaziridines, oxazolines,oxazolidinones, ring-opening, regioselective,diastereoselective, sphingosine, configuration, NMRspectroscopy.NR 2014080
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Divergent synthesis of D-erythro-sphingosine, L-threo-sphingosine, and their regioisomers.
The Journal of organic chemistry, 2003Co-Authors: Berit Olofsson, Peter SomfaiAbstract:Starting from a vinyl epoxide, a divergent synthesis of four sphingosine isomers is described. The remaining four isomers can easily be synthesized using the same methodology. Although numerous syntheses of sphingosine have been published, this is the first general route leading to all eight isomers in this important compound class. The synthetic strategy relies on regioselective opening of a vinyl epoxide and a vinylaziridine in the allylic position.
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A regio- and stereodivergent route to all isomers of vic-amino alcohols.
The Journal of organic chemistry, 2002Co-Authors: Berit Olofsson, Peter SomfaiAbstract:Vicinal amino alcohols are substructures in several important natural products. They are also frequently employed ligands in asymmetric synthesis. Many enantioselective syntheses of vic-amino alcohols have been reported, but each structure has required its own synthetic route. This study presents a synthetic strategy leading to all eight possible isomers of a given β-amino alcohol, starting from vinyl epoxides. The developed strategy focuses on the propensity of vinyl epoxides and Vinylaziridines to be selectively ring-opened at the allylic position by suitable hard nucleophiles. Within this strategy, a novel large-scale aminolysis reaction and the synthesis of a trisubstituted N-H vinylaziridine are detailed.
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Synthesis of N-H Vinylaziridines : a comparative study.
Tetrahedron, 2002Co-Authors: Berit Olofsson, Roel Wijtmans, Peter SomfaiAbstract:Vinylaziridines are useful and versatile synthetic intermediates, as the relief of ring-strain provides a driving force for efficient ring-opening or ring-expansion reactions. Furthermore, the vinyl group can be derivatized into interesting functionalities. The ring-closure of vicinal amino alcohols constitutes a straightforward route to aziridines. Several methods exist for this transformation, although many cannot be applied to Vinylaziridines due to their acid lability. This comparative study describes the most effective sequences for the formation of N-H Vinylaziridines.
Chaojie Wang - One of the best experts on this subject based on the ideXlab platform.
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Visible-Light Photoredox-Catalyzed Formal [5 + 1] Cycloaddition of N-Tosyl Vinylaziridines with Difluoroalkyl Halides.
Organic letters, 2020Co-Authors: Yantao Liu, Wen Luo, Zhenjie Wang, Yuxin Zhao, Jingjing Zhao, Chaojie WangAbstract:A visible-light photoredox-catalyzed formal [5 + 1] cycloaddition of N-tosyl Vinylaziridines with difluoroalkyl halides as unique C1 synthons was developed. The procedure provides an efficient and practical method to synthesize diverse pyridines in moderate to good yields. The reaction underwent a radical-initiated kinetically controlled ring-opening of Vinylaziridines and involved a key α,β-unsaturated imine intermediate, followed by an E2 elimination, a 6π electrocyclization, and defluorinated aromatization.
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visible light photoredox catalyzed formal 5 1 cycloaddition of n tosyl Vinylaziridines with difluoroalkyl halides
Organic Letters, 2020Co-Authors: Yantao Liu, Wen Luo, Zhenjie Wang, Yuxin Zhao, Jingjing Zhao, Chaojie WangAbstract:A visible-light photoredox-catalyzed formal [5 + 1] cycloaddition of N-tosyl Vinylaziridines with difluoroalkyl halides as unique C1 synthons was developed. The procedure provides an efficient and practical method to synthesize diverse pyridines in moderate to good yields. The reaction underwent a radical-initiated kinetically controlled ring-opening of Vinylaziridines and involved a key α,β-unsaturated imine intermediate, followed by an E2 elimination, a 6π electrocyclization, and defluorinated aromatization.
Wen-jing Xiao - One of the best experts on this subject based on the ideXlab platform.
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Visible-Light-Driven Nitrogen Radical-Catalyzed [3 + 2] Cyclization of Vinylcyclopropanes and N-Tosyl Vinylaziridines with Alkenes.
Organic letters, 2020Co-Authors: Quan-qing Zhao, Xue‐song Zhou, Wen-jing Xiao, Jia-rong ChenAbstract:A visible light photoredox-promoted and nitrogen radical catalyzed [3 + 2] cyclization of vinylcyclopropanes and N-tosyl Vinylaziridines with alkenes is developed. Key to the success of this proces...
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visible light driven nitrogen radical catalyzed 3 2 cyclization of vinylcyclopropanes and n tosyl Vinylaziridines with alkenes
Organic Letters, 2020Co-Authors: Quan-qing Zhao, Wen-jing Xiao, Xuesong Zhou, Jia-rong ChenAbstract:A visible light photoredox-promoted and nitrogen radical catalyzed [3 + 2] cyclization of vinylcyclopropanes and N-tosyl Vinylaziridines with alkenes is developed. Key to the success of this proces...
