- Copper-catalyzed ring-opening reactions of alkyl aziridines with b2 pin2: Experimental and computational studies
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The possibility to form new C–B bonds with aziridines using diboron derivatives con-tinues to be a particularly challenging field in view of the direct preparation of functionalized β-aminoboronates, which are important compounds in drug discovery, being a bioisostere of β-aminoacids. We now report experimental and computational data that allows the individua-tion of the structural requisites and of reaction conditions necessary to open alkyl aziridines using bis(pinacolate)diboron (B2 pin2 ) in a regioselective nucleophilic addition reaction under copper catalysis.
- Boldrini, Cosimo,Comparini, Lucrezia Margherita,Di Bussolo, Valeria,Di Pietro, Sebastiano,Favero, Lucilla,Menichetti, Andrea,Pineschi, Mauro
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supporting information
(2021/12/17)
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- Titanium and Cobalt Bimetallic Radical Redox Relay for the Isomerization of N -Bz Aziridines to Allylic Amides
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Herein a bimetallic radical redox-relay strategy is employed to generate alkyl radicals under mild conditions with titanium(III) catalysis and terminated via hydrogen atom transfer with cobalt(II) catalysis to enact base-free isomerizations of N-Bz aziridines to N-Bz allylic amides. This reaction provides an alternative strategy for the synthesis of allylic amides from alkenes via a three-step sequence to accomplish a formal transpositional allylic amination.
- Wood, Devin P.,Guan, Weiyang,Lin, Song
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supporting information
p. 4213 - 4220
(2021/08/10)
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- Activation of carboxylic acids in asymmetric organocatalysis
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Organocatalysis, catalysis using small organic molecules, has recently evolved into a general approach for asymmetric synthesis, complementing both metal catalysis and biocatalysis.1 Its success relies to a large extent upon the introduction of novel and generic activation modes.2 Remarkably though, while carboxylic acids have been used as catalyst directing groups in supramolecular transition-metal catalysis,3 a general and well-defined activation mode for this useful and abundant substance class is still lacking. Herein we propose the heterodimeric association of carboxylic acids with chiral phosphoric acid catalysts as a new activation principle for organocatalysis. This self-assembly increases both the acidity of the phosphoric acid catalyst and the reactivity of the carboxylic acid. To illustrate this principle, we apply our concept in a general and highly enantioselective catalytic aziridine-opening reaction with carboxylic acids as nucleophiles. Activation by dimerization: There is still no general activation mode for carboxylic acids in organocatalysis. The formation of heterodimers between chiral phosphoric acid diesters and carboxylic acids can be used to activate and direct reactivity of the latter in asymmetric reactions. This novel principle has been applied to the ring-opening desymmetrization and kinetic resolution of aziridines leading to valuable amino alcohols.
- Monaco, Mattia Riccardo,Poladura, Belen,Diaz De Los Bernardos, Miriam,Leutzsch, Markus,Goddard, Richard,List, Benjamin
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p. 7063 - 7067
(2014/07/08)
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- Scalable synthesis of N -acylaziridines from N -tosylaziridines
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N-Acylaziridines are important starting materials for the synthesis of chiral amine derivatives. The traditional methods for producing these activated aziridines have significant drawbacks. The gram scale synthesis of N-acylaziridines by deprotection of N
- Rubin, Heather,Cockrell, Jennifer,Morgan, Jeremy B.
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p. 8865 - 8871
(2013/09/24)
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- Chemoenzymatic synthesis of optically active cis- and trans-2-(1H-Imidazol- 1-yl)cycloalkanamines
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The preparation of enantiopure 2-(1H-imidazol-1-yl)cycloalkanamines has been studied by independent chemoenzymatic approaches. We first explored a route involving the enzymatic resolution of racemic cycloalkanol analogs for the preparation of the correspo
- Alatorre-Santamaria, Sergio,Gotor-Fernandez, Vicente,Gotor, Vicente
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experimental part
p. 1057 - 1063
(2011/04/17)
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- Ring-opening of NH-aziridines with thiols in ionic liquids: Application to the synthesis of aminosulfide catalysts for asymmetric epoxidation of aldehydes
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The ring opening of NH-aziridines with thiols was found to proceed in good yield at room temperature in the presence of an ionic liquid1-butyl-3- methylimidazolium chloride (BMIM chloride). This mild methodology was applied to the synthesis of a camphor-derived chiral aminosulfide. The sulfide was used to generate a sulfur ylide, which effected an asymmetric epoxidation of benzaldehyde (e.r. 85:15, trans:cis 90:10, 87% yield). The amino group enabled easy recovery of the sulfide (98% yield) after the reaction by a simple acid/base extraction. Copyright Taylor & Francis Group.
- Namutebi, Mariam,McGarrigle, Eoghan M.,Aggarwal, Varinder K.
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scheme or table
p. 1250 - 1272
(2010/08/21)
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- Enantioselective desymmetrization of meso-aziridines with TMSN3 or TMSCN catalyzed by discrete yttrium complexes
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(Chemical Equation Presented) Y is it so? Dimeric yttrium-salen complexes (see structure; N blue, O red, Y magenta) catalyze the highly enantioselective ring-opening of meso-aziridines by TMSCN and TMSN3. To explain the dramatic differences in
- Wu, Bin,Gallucci, Judith C.,Parquette, Jon R.,RajanBabu
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supporting information; experimental part
p. 1126 - 1129
(2009/06/20)
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- Enantioselective ring-opening of aziridines
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A process for the preparation of a nucleophilic addition product of an aziridine and a nucleophile, the process comprising treating the arizidine with the nucleophile in the presence of a biaryl phosphoric acid catalyst
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Page/Page column 15
(2009/02/11)
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- Bronsted acid-catalyzed desymmetrization of meso-aziridines
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The enantioselective ring-opening of meso-aziridines with azide nucleophiles proceeded in the presence of a catalytic amount of a chiral phosphoric acid catalyst. The reaction affords the formation of the products in excellent yield and enantioselectivity. Preliminary mechanistic studies indicate that the active catalytic species is a chiral silane that is generated in situ. Copyright
- Rowland, Emily B.,Rowland, Gerald B.,Rivera-Otero, Edwin,Antilla, Jon C.
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p. 12084 - 12085
(2008/04/11)
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- Asymmetric Catalysis by Vitamin B12: The Isomerization of Achiral Aziridines to Optically Active Allylic Amines
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Achiral N-acylaziridines are isomerized to optically active N-acyl-allylamines in ee's of up to 95percent by catalytic amounts of cob(I)alamin in MeOH.
- Zhang, Zhong da,Scheffold, Rolf
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p. 2602 - 2615
(2007/10/02)
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- Compounds with Bridgehead Nitrogen. Part 43. The Reaction between trans-2-Aminocycloalkanethiols and Formaldehyde
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trans-2-Aminocyclopentanethiol condenses with formaldehyde to give rel-(3aR,6aR,9aR,12aR)-6,12-methanoperhydrodicyclopentanodithiadiazecine, whereas trans-2-aminocyclohexanethiol and trans-2-aminocycloheptanethiol give 1:1 mixture of diastereomeric bis(perhydrocycloalkanothiazol-3-yl)methanes.
- Barkworth, Peter M. R.,Crabb, Trevor A.
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p. 2777 - 2782
(2007/10/02)
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