- On the Mechanism of the Aziridine Synthesis from 2-Azido-alcohols and Triphenylphosphine
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The reaction of selected 2-azido-alcohols, their pivalates, and methanesulfonates with triphenylphosphine was investigated.It is shown that the formation of aziridines from 2-azido-alcohols proceeds via 1,3,2λ5-oxazaphospholidines.Furthermore, the first synthesis of the unsubstituted acenaphthene-1,2-imine is described.
- Poechlauer, Peter,Mueller, Ernst Peter,Peringer, Paul
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Read Online
- Chiral sulfide - phosphine ligand and preparation method and use thereof
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The present invention provides a novel chiral thioether-phosphine ligand and a preparation method and application thereof. The ligand is a compound shown as a formula I, or enantiomer, non-enantiomer, racemate, pharmaceutically acceptable salt, hydrate and solvate crystal thereof. R1 is an optionally substituted phenyl, and optionally substituted naphthyl; and R2 is methyl and benzyl. The chiral thioether-phosphine ligand provided by the invention as a copper-catalyzed asymmetric cycloaddition ligand can be directly used to prepare various pyrrolidine compounds with substituted multiple chiral centers.
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Paragraph 0059; 0069; 0079; 0089; 0099; 0109; 0120
(2017/08/25)
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- Enantioselective synthesis of tetrahydrofuran derivatives by sequential henry reaction and iodocyclization of γ,δ-unsaturated alcohols
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A sequential one-pot Cu-catalyzed asymmetric Henry reaction and iodocyclization is disclosed. The transformation provides efficient access to biologically and synthetically useful 2,2,5-trisubstituted tetrahydrofuran derivatives. The combination of Cu(OAc)2·H2O with a novel chiral sulfoxide-Schiff base hybrid ligand under mild reaction conditions tolerates a wide range of 4-substituted γ,δ-unsaturated aldehydes, and the subsequent iodocyclization furnishes the corresponding products in generally high yields with excellent enantioselectivities. The products can be easily converted into amines with excellent diastereo- and enantioselectivities.
- Chen, Li-Yan,Chen, Jia-Rong,Cheng, Hong-Gang,Lu, Liang-Qiu,Xiao, Wen-Jing
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supporting information
p. 4714 - 4719
(2014/08/05)
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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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- Design of chiral sulfoxide-Schiff base hybrids and their application in Cu-catalyzed asymmetric Henry reactions
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A new class of chiral sulfoxide-Schiff base ligands has been developed by the rational combination of two privileged chiral backbones. These sulfoxide-Schiff base ligands were found to be highly efficient for Cu-catalyzed asymmetric Henry reactions (up to
- Cheng, Hong-Gang,Lu, Liang-Qiu,Wang, Tao,Chen, Jia-Rong,Xiao, Wen-Jing
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supporting information; experimental part
p. 5596 - 5598
(2012/07/03)
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- Synthesis and structure of hypervalent diacetoxybromobenzene and aziridination of olefins with imino-λ3-bromane generated in situ under metal-free conditions
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Ligand exchange of p-CF3C6H4BrF 2 with acetoxy groups using AcOH and Ac2O affords (diacetoxybromo)benzene in a high yield, which undergoes aziridination of alkenes in the presence of TfNH2
- Hoque, Md. Mahbubul,Miyamoto, Kazunori,Tada, Norihiro,Shiro, Motoo,Ochiai, Masahito
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p. 5428 - 5431
(2011/11/30)
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- 2-(p-Tolylsulfinyl)benzyl halides as efficient precursors of optically pure trans-2,3-Disubstituted aziridines
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Aziridination of (R)-N-sulfinylaldimines (aryl, heteroaryl and alkenyl derivatives) with 2-(p-tolyl sulfinyl)benzyl iodide in the presence of sodium hexamethyl disilazide takes place with almost complete control of the stereoselectivity (facial and antil
- Arroyo, Yolanda,Meana, Angela,Sanz-Tejedor, M. Ascension,Alonso, Ines,Garcia Ruano, Jose Luis
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experimental part
p. 9874 - 9883
(2010/10/04)
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- Stereoselective control of planar α-dimethylsulfonium benzyl carbanions. Synthesis of optically pure trans-aziridines
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(Chemical Equation Presented) (R)-N-Sulfinylimine and (S)-N-sulfinylimine react with the ylide derived from (S)-dimethyl-[2-(p-toluenesulfinyl) phenyl]sulfonium salt, affording trans-2,3-disubstituted aziridines. A complete trans selectivity in low facial
- Arroyo, Yolanda,Meana, Angela,Rodriguez, J. Felix,Sanz-Tejedor, M. Ascension,Alonso, Ines,Ruano, Jose L. Garcia
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experimental part
p. 4217 - 4224
(2009/09/25)
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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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- Aminosulf(ox)ides as Ligands for Iridium(I)-Catalyzed Asymmetric Transfer Hydrogenation
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A new class of efficient catalysts was developed for the asymmetric transfer hydrogenation of unsymmetrical ketones. A series of chiral N,S-chelates (6-22) was synthesized to serve as ligands in the iridium(I)-catalyzed reduction of ketones. Both formic a
- Petra, Danielle G. I.,Kamer, Paul C. J.,Spek, Anthony L.,Schoemaker, Hans E.,Van Leeuwen, Piet W. N. M.
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p. 3010 - 3017
(2007/10/03)
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- Studies on a Chiral (N,P) Ligand Containing a C2-Symmetric Aziridine Unit
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As part of a program on the use of chiral aziridines in asymmetric synthesis and catalysis, the enantiopure (N,P) ligand 1, consisting of a C2-symmetric chiral aziridine and a triarylphosphine unit, was prepared. The synthesis was convergent and efficient, proceeding in five steps and 37% overall yield from 2-bromotoluene. The ligand was designed (a) for a study of the asymmetric Pd-catalyzed allylic substitution reaction, (b) in an attempt to obtain a measure of the trans effect of phosphorus relative to an aziridine nitrogen, and (c) to compare its performance with the corresponding chiral phosphinooxazoline species (computational studies having indicated certain similarities between the two ligand types). However, the new aziridine species did not provide levels of enantioselectivity comparable to those obtained with the phosphinooxazoline analogs, and our results serve to underline once more the difficulties associated with the rational design of ligands for asymmetric catalysis.
- Tanner, David,Wyatt, Paul,Johansson, Fredrik,Bertilsson, Sophie K.,Andersson, Pher G.
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p. 263 - 268
(2007/10/03)
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- Synthesis of Homochiral Amino Alcohols, Aziridines and Diamines via Homochiral Cyclic Sulphites
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Vicinal diols react with thionyl chloride to give 1,2-cyclic sulphites in quantitative yield, which undergo facile ring opening by lithium azide in dimethylformamide to yield azido alcohols and the latter in turn have been stereoselectively transformed into amino alcohols, aziridines and diamines.
- Lohray, Braj B.,Ahuja, Jaimala R.
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- Stereoselective Synthesis of cis-2,3-Diarylaziridine by Rearrangement of Aryl-Substituted N-(Silylmethyl)imine
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Thermal rearrangement of aryl-substituted N-(silylmethyl)imines to N-silylaziridines with high cis-selectivity was revealed and workup of the products readily led to cis-aziridine derivatives.
- Komatsu, Mitsuo,Ohno, Mitsuru,Tsuno, Shingo,Ohshiro, Yoshiki
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p. 575 - 576
(2007/10/02)
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- PHOTOISOMERISATION OF 2,3,6,7-TETRAPHENYL-1,2,3-TRIAZOLO-1,2,3-TRIAZOLE
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Irradiation of the title compound brings about consecutive photoisomerisations via derivatives of 1,2,3-triazolyl-2H-azirine, 1,2,3-triazolo-1,2,4-triazole and 1,2,4-triazolyl-2H-azirine, leading finally to a dehydrotetraazabenzazulene.
- Kopecky, Jan,Smejkal, Jaroslav,Turecek, Frantisek,Jirkovsky, Jaromir,Fojtik, Anton,Hanus, Vladimir
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p. 2613 - 2616
(2007/10/02)
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- Umsetzung von 2-Azidoalkoholen mit Trialkylphosphiten. Bildung von Aziridinen und Amidophosphorsaeureestern via Imidophosphorsaeureester und 1,3,2λ5-Oxazaphospholidine
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The 2-azidoalcohols 1 and 2 react with trialkyl phosphites to trialkyl (2-hydroxyalkyl)imidophosphates 10, 14, and 15 respectively, whereas the 2-azidoalcohols 3-7 yield the 2,2,2-trialkoxy-1,3,2λ5-oxazaphospholidines 16-22 under the same reaction conditions (Scheme 2).The dialkyl (2-hydroxyalkyl)amidophosphates 23, 25, and 27-34 are obtained by the reaction of 10, and 14-22 with water (Scheme 3 and 4).By reaction with alcohols, however, both the imidophosphates 10, 14, and 15 and the 1,3,2λ5-oxazaphospholidines 16-22 are transformed to aziridines 24, 26, and 35-38 (S cheme 5).The reactions of the imidophosphates seem to proceed via 1,3,2λ5-oxazaphospholidines.
- Willeit, Armin,Mueller, Ernst Peter,Peringer, Paul
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p. 2467 - 2480
(2007/10/02)
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- REACTIVITY OF N,N-DICHLOROURETHANES. XI. ADDITION OF N,N-DICHLOROURETHANES TO trans-STILBENE
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N,N-Dichlorourethanes add readily to trans-stilbene with the formation of alkyl N-chloro-N-(2-chloro-1,2-diphenylethyl)carbamates, which give alkyl N-(2-chloro-1,2-diphenylethyl)carbamates when treated with an aqueous solution of sodium sulfite or thiosul
- Bal'on, Ya. G.,Moskaleva, R. N.
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p. 2227 - 2232
(2007/10/02)
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