- Additions of stabilised and semi-stabilised sulfur ylides to tosyl protected imines: Are they under kinetic or thermodynamic control?
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Sulfur ylides react with imines, via betaines, to give aziridines. We sought to determine whether betaine formation was reversible in reactions of benzyl-, amide- and ester-stabilised ylides by carrying out cross-over experiments. Thus, the intermediate betaines were generated independently from the corresponding sulfonium salt in the presence of a more reactive imine (p-nitrobenzaldimine). It was found that no incorporation of the more reactive imine was observed in reactions with the benzyl-stabilised ylide, whilst >80% incorporation of the p-nitrobenzaldimine was observed from the ester- and amide-stabilised ylides. These results indicate that benzyl-stabilised ylides react irreversibly with imines but ester- and amide-stabilised react reversibly. Thus, the stereocontrolling step of the process is dependent on the type of ylide employed and the results are used to account for the different diastereoselectivities observed with the different ylides.
- Aggarwal, Varinder K.,Charmant, Jonathan P.H.,Ciampi, Cinzia,Hornby, Jonathan M.,O'Brien, Christopher J.,Hynd, George,Parsons, Richard
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Read Online
- Catalytic cyclopropanation and aziridination of alkenes by a Cu(I) complex of ferrocenyldiimine
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The copper(I) complex (FcNN)Cu(OTf) (1; FcNN = N,N′-ethylenebis[(ferrocenylmethylene)amine] catalyzes reactions of ethyl diazoacetate with alkenes to form cyclopropanes in high yield. The same complex also catalyzes nitrene transfer from PhI=NTs to alkene
- Cho, Dong-Jei,Jeon, Sang-Jin,Kim, Hong-Seok,Kim, Tae-Jeong
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Read Online
- A facile C-arylation of N-tosyl aziridines via Ag(I) catalysis
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N-Tosyl aziridines react with a variety of arenes and heteroarenes in the presence of 1-2% of silver hexafluorophosphate at room temperature to afford the corresponding β-aryl amine derivatives in excellent yields and with high regioselectivity.
- Bera, Milan,Roy, Sujit
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Read Online
- Is the Electrophilicity of the Metal Nitrene the Sole Predictor of Metal-Mediated Nitrene Transfer to Olefins? Secondary Contributing Factors as Revealed by a Library of High-Spin Co(II) Reagents
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Recent research has highlighted the key role played by the electron affinity of the active metal-nitrene/imido oxidant as the driving force in nitrene additions to olefins to afford valuable aziridines. The present work showcases a library of Co(II) reage
- Kalra, Anshika,Bagchi, Vivek,Paraskevopoulou, Patrina,Das, Purak,Ai, Lin,Sanakis, Yiannis,Raptopoulos, Grigorios,Mohapatra, Sudip,Choudhury, Amitava,Sun, Zhicheng,Cundari, Thomas R.,Stavropoulos, Pericles
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p. 1974 - 1996
(2021/06/28)
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- Chiral bis(pyrazolyl)methane copper(I) complexes and their application in nitrene transfer reactions
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In this study, chiral bis(pyrazolyl)methane copper(I) acetonitrile complexes were applied to generate two novel terminal copper tosyl nitrene complexes with the nitrene generating agent SPhINTs in dichloromethane at low temperatures. The syntheses of the chiral bis(pyrazolyl)methane ligands are based on pulegone and camphor, members of the natural chiral pool. The chiral copper(I) acetonitrile complexes were applied as catalysts in the copper nitrene mediated aziridination reaction of different styrene derivatives and the C-H amination of various substrates. The reactions afforded good yields, but low enantiomeric excess under mild conditions. The nitrene species have been characterized with UV/Vis and EPR spectroscopy and the products of the decay by ESI mass spectrometry.
- Thomas, Fabian,Steden, Dominik,Eith, Alexander,Hoffmann, Alexander,Herres-Pawlis, Sonja
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p. 835 - 847
(2021/11/09)
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- Iron(ii)-catalyzed intermolecular aziridination of alkenes employing hydroxylamine derivatives as clean nitrene sources
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The iron-catalyzed intermolecular aziridination of alkenes with hydroxylamine derivatives is described. Using simple iron(ii) sources and readily available ligands, the formal (2 + 1) cycloaddition process proved to be efficient on both styrenes and aliphatic alkenes, providing access to a wide range of aziridines. In these particularly sustainable reaction conditions, yields up to 89% could be obtained, with a catalyst loading which could be lowered to 5 mol% when the reaction was performed on large scale. Preliminary mechanistic studies suggest that both concerted and stepwise pathways are operating in this transformation. This journal is
- Berhal, Farouk,Grimaud, Laurence,Kirby, Georgina,Prestat, Guillaume,Vitale, Maxime R.
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p. 9428 - 9432
(2021/12/09)
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- A Dicopper Nitrenoid by Oxidation of a CuICuICore: Synthesis, Electronic Structure, and Reactivity
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A dicopper nitrenoid complex was prepared by formal oxidative addition of the nitrenoid fragment to a dicopper(I) center by reaction with the iminoiodinane PhINTs (Ts = tosylate). This nitrenoid complex, (DPFN)Cu2(μ-NTs)[NTf2]2 (DPFN = 2,7-bis(fluorodi(2-pyridyl)methyl)-1,8-naphthyridine), is a powerful H atom abstractor that reacts with a range of strong C-H bonds to form a mixed-valence Cu(I)/Cu(II) μ-NHTs amido complex in the first example of a clean H atom transfer to a dicopper nitrenoid core. In line with this reactivity, DFT calculations reveal that the nitrenoid is best described as an iminyl (NR radical anion) complex. The nitrenoid was trapped by the addition of water to form a mixed-donor hydroxo/amido dicopper(II) complex, which was independently obtained by reaction of a Cu2(μ-OH)2 complex with an amine through a protonolysis pathway. This mixed-donor complex is an analogue for the proposed intermediate in copper-catalyzed Chan-Evans-Lam coupling, which proceeds via C-X (X = N or O) bond formation. Treatment of the dicopper(II) mixed donor complex with MgPh2(THF)2 resulted in generation of a mixture that includes both phenol and a previously reported dicopper(I) bridging phenyl complex, illustrating that both reduction of dicopper(II) to dicopper(I) and concomitant C-X bond formation are feasible.
- Desnoyer, Addison N.,Nicolay, Amélie,Ziegler, Micah S.,Lakshmi,Cundari, Thomas R.,Tilley, T. Don
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supporting information
p. 7135 - 7143
(2021/05/31)
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- First Sustainable Aziridination of Olefins Using Recyclable Copper-Immobilized Magnetic Nanoparticles
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The first copper-catalyzed aziridination of olefins using recyclable magnetic nanoparticles is described. Magnetic nanoparticles were modified with dopamine and used as a support to coordinate copper. The methodology was optimized with styrene as olefin a
- Khodadadi, Mohamad Reza,Pourceau, Gwladys,Becuwe, Matthieu,Wadouachi, Anne,Toumieux, Sylvestre
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supporting information
p. 563 - 566
(2019/03/08)
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- Regiodivergent and Stereospecific Aziridine Opening by Copper-Catalyzed Addition of Silicon Grignard Reagents
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A stereospecific ring opening of various 2-aryl-substituted aziridines with silicon Grignard reagents under copper catalysis is reported. The regiochemical outcome is governed by the steric demand of the silicon nucleophile. The LiCl introduced with the m
- Yi, Hong,Oestreich, Martin
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supporting information
p. 6505 - 6507
(2019/04/30)
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- Organocatalytic nitrenoid transfer: Metal-free selective intermolecular C(sp3)-H amination catalyzed by an iminium salt
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This report details the first organocatalytic method for nitrenoid transfer and its application to intermolecular, site-selective C(sp3)-H amination. The method utilizes a trifluoromethyl iminium salt as the catalyst, iminoiodinanes as the nitrogen source, and substrate as the limiting reagent. Activated, benzylic, and aliphatic substrates can all be selectively functionalized in yields up to 87%. A mechanistic proposal for the observed reactivity supported by experimental evidence invokes the intermediacy of a diaziridinium salt or related organic nitrenoid, species that have not been previously explored for the purpose of C-H amination. Finally, examples of late-stage functionalization of complex molecules highlight the selectivity and potential utility of this catalytic method in synthesis.
- Combee, Logan A.,Raya, Balaram,Wang, Daoyong,Hilinski, Michael K.
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p. 935 - 939
(2018/02/07)
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- Branched Amine Synthesis via Aziridine or Azetidine Opening with Organotrifluoroborates by Cooperative Br?nsted/Lewis Acid Catalysis: An Acid-Dependent Divergent Mechanism
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A practical catalytic method to synthesize β,β- and γ,γ-substituted amines by opening aziridines and azetidines, respectively, using alkenyl, alkynyl, or aryl/heteroaryl trifluoroborate salts is described. This reaction features simple open-flask reaction conditions, the use of transition-metal-free catalysis, complete regioselectivity, and high diastereoselectivity. Preliminary mechanistic studies suggest that carbocation formation is disfavored. Stereoretentive addition is favored with Br?nsted acid present, while stereoinversion is favored in its absence, indicating divergent mechanisms.
- Nguyen, Truong N.,May, Jeremy A.
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p. 3618 - 3621
(2018/06/26)
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- Alkene functionalization for the stereospecific synthesis of substituted aziridines by visible-light photoredox catalysis
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A novel strategy involving visible-light-induced functionalization of alkenes for the synthesis of substituted aziridines was developed. The readily prepared N-protected 1-aminopyridinium salts were used for the generation of N-centered radicals. This approach allowed the synthesis of aziridines bearing various functional groups with excellent diastereoselectivity under mild conditions. Moreover, this protocol was successfully applied to prepare structurally diverse nitrogen-containing frameworks.
- Yu, Wan-Lei,Chen, Jian-Qiang,Wei, Yun-Long,Wang, Zhu-Yin,Xu, Peng-Fei
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p. 1948 - 1951
(2018/03/01)
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- Grafting of copper(II) Schiff base complex on functionalized multi-wall carbon nanotubes: Synthesis, characterization and catalytic aziridination of olefins
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In this study, hydroxyl functionalized copper(II) Schiff-base; [Cu((OH)2-salophen)], [(OH)2-salophen] = (N,N-bis(4-hydroxysalicylidene) phenylene-1,2-diamine); has been covalently anchored on modified multi-wall carbon nanotubes (MWN
- Bazarganipour, Mehdi,Salavati-Niasari, Masoud
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- Regioselective Ring-Opening Nucleophilic Addition of Aziridines through Photoredox Catalyst
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A mild and efficient procedure was developed for the regioselective ring-opening nucleophilic addition reactions of aziridines via visible light photoredox catalysis, that provides a practical synthetic access to 1,2-bifunctional compounds. Furthermore, the regioselective synthesis of non-racemic amino ethers from chiral aziridine could also be achieved under mild conditions. Finally, a possible reaction mechanism was proposed and further supported by control experiments.
- Sun, Hongnan,Yang, Chao,Lin, Run,Xia, Wujiong
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supporting information
p. 2775 - 2780
(2016/02/18)
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- Syntheses of a novel fluorinated trisphosphinoborate ligand and its copper and silver complexes. Catalytic activity toward nitrene transfer reactions
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A novel fluorinated ligand, the anionic PhB(CH2P(p-CF 3C6H4)2)3 (PhBP 3 p-CF3Ph), has been synthesized and characterized, as well as its corresponding thallium, copper
- Arenas, Ismael,Fuentes, M. Angeles,Alvarez, Eleuterio,Diaz, Yolanda,Caballero, Ana,Castillon, Sergio,Perez, Pedro J.
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p. 3991 - 3999
(2014/05/06)
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- Metal-free aziridination of styrene derivatives with iminoiodinane catalyzed by a combination of iodine and ammonium iodide
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The metal-free catalytic aziridination of styrene derivatives with N-tosyliminophenyliodinane (PhI=NTs) in the presence of a combination of I 2 and tetrabutylammonium iodide (TBAI) is reported. In situ generated TBAI3 from I2/s
- Kiyokawa, Kensuke,Kosaka, Tomoki,Minakata, Satoshi
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supporting information
p. 4858 - 4861
(2013/10/08)
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- Practical and highly selective sulfur ylide-mediated asymmetric epoxidations and aziridinations using a cheap and readily available chiral sulfide: Extensive studies to map out scope, limitations, and rationalization of diastereo- and enantioselectivities
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The chiral sulfide, isothiocineole, has been synthesized in one step from elemental sulfur, γ-terpinene, and limonene in 61% yield. A mechanism involving radical intermediates for this reaction is proposed based on experimental evidence. The application of isothiocineole to the asymmetric epoxidation of aldehydes and the aziridination of imines is described. Excellent enantioselectivities and diastereoselectivities have been obtained over a wide range of aromatic, aliphatic, and α,β-unsaturated aldehydes using simple protocols. In aziridinations, excellent enantioselectivities and good diastereoselectivities were obtained for a wide range of imines. Mechanistic models have been put forward to rationalize the high selectivities observed, which should enable the sulfide to be used with confidence in synthesis. In epoxidations, the degree of reversibility in betaine formation dominates both the diastereoselectivity and the enantioselectivity. Appropriate tuning of reaction conditions based on understanding the reaction mechanism enables high selectivities to be obtained in most cases. In aziridinations, betaine formation is nonreversible with semistabilized ylides and diastereoselectivities are determined in the betaine forming step and are more variable as a result.
- Illa, Ona,Namutebi, Mariam,Saha, Chandreyee,Ostovar, Mehrnoosh,Chen, C. Chun,Haddow, Mairi F.,Nocquet-Thibault, Sophie,Lusi, Matteo,McGarrigle, Eoghan M.,Aggarwal, Varinder K.
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supporting information
p. 11951 - 11966
(2013/09/02)
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- Nanocrystalline zinc peroxide mediated unprecedented nitrene transfer: An expeditious access to N-tosylaziridines
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An unprecedented zinc peroxide (ZnO2) assisted synthetic strategy is reported for the synthesis of N-tosylaziridines from alkenes by using N-tosyliminotriphenylphosphorane (Ph3PNTs) as a nitrene transfer reagent under mild reaction conditions. The reaction of zinc peroxide with Ph3PNTs yielded a zinc oxaziridine intermediate which subsequently reacts with alkenes to give corresponding N-tosylaziridines in high to excellent yields. The Royal Society of Chemistry 2013.
- Verma, Sanny,Jain, Suman L.
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p. 19830 - 19833
(2013/11/06)
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- Nickel-catalyzed negishi alkylations of styrenyl aziridines
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A nickel-catalyzed cross-coupling reaction between N-sulfonyl aziridines and organozinc reagents is reported. The catalytic system comprises an inexpensive and air-stable Ni(II) source and dimethyl fumarate as ligand. Regioselective synthesis of β-substituted amines is possible under mild and functional-group-tolerant conditions. The stereoselectivity of the reaction is consistent with a stereoconvergent mechanism wherein the sulfonamide directs C-C bond formation.
- Huang, Chung-Yang,Doyle, Abigail G.
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supporting information; experimental part
p. 9541 - 9544
(2012/07/14)
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- Ag(I)-catalyzed regioselective ring-opening of N -tosylaziridine and N -tosylazetidine with S -, O -, and N -nucleophiles and tethered dinucleophiles
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[Ag(COD)2]PF6 catalyzes the ring-opening of N-tosylaziridines and -azetidines with alcohols, amines, thiols, and related tethered 1,2-ethane dinucleophiles. Initial rate studies and DFT-based evaluation of stepwise energetics suggest
- Bera, Milan,Pratihar, Sanjay,Roy, Sujit
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supporting information; experimental part
p. 1475 - 1478
(2011/04/27)
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- Silver(I)-Diene complexes as versatile catalysts for the C -Arylation of N -Tosylaziridines: Mechanistic insight from in situ diagnostics
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(Figure presented) Silver(I) complex [Ag(diene)2] +Y- (where diene = cyclooctadiene, norbornadiene, and 1,3-cyclohexadiene; Y- = PF6-, BF 4-) efficiently catalyzes the
- Bera, Milan,Roy, Sujit
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experimental part
p. 4402 - 4412
(2010/10/01)
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- 1,3,5-Tris(thiocyanatomethyl)mesitylene as a Ligand. Pseudooctahedral molybdenum, manganese, and rhenium carbonyl complexes and copper and silver dimers. Copper-catalyzed carbene- and nitrene-transfer reactions
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New molybdenum(0), molybdenum(II), manganese(I), rhenium(I), silver(I), and copper(I) complexes with the 1,3,5-tris(thiocyanatomethyl)mesitylene [Ms(CH2SCN)3] ligand have been synthesized and characterized by IR, NMR, and by X-ray diffraction (except for the rhenium complex). The Ms(CH2SCN)3 ligand coordinated with the molybdenum, manganese, and rhenium carbonyl fragments as a tripodal chelate. With copper and silver, dimeric dicationic species were obtained instead, with the Ms(CH2SCN)3 ligand acting simultaneously as a bidentate chelate and bridge. The [{Cu(Ms(CH2SCN)3)} 2][BAr′4]2 (BAr′4 = tetra(3,5-bis(trifluoromethyl)phenyl)borate) product is an excellent catalyst for cyclopropanation and aziridination of alkenes and cyclopropenation of alkynes by means of carbene- and nitrene-transfer reactions.
- Martinez-Garcia, Hector,Morales, Dolores,Perez, Julio,Puerto, Marcos,Miguel, Daniel
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experimental part
p. 6974 - 6985
(2010/09/06)
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- NaIO4/LiBr-mediated aziridination of olefins using chloramine-T
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A new milder protocol for aziridination of a variety of olefins has been described. The process employs catalytic amount of sodium metaperiodate (NaIO4) as an oxidant and LiBr and chloramine-T as the bromine and nitrogen sources, respectively. Interestingly, the formation of aziridine products in all the cases studied takes place presumably through a process of 1,2-aminobromination of alkenes.
- Karabal, Pratibha U.,Chouthaiwale, Pandurang V.,Shaikh, Tanveer M.,Suryavanshi, Gurunath,Sudalai, Arumugam
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experimental part
p. 6460 - 6462
(2011/01/03)
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- Sulfur ylide promoted synthesis of N-protected aziridines: A combined experimental and computational approach
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A range of N-protected aziridines [N-Tosyl (N-Ts), N-2- trimethylsilylethanesulfonamide (N-SES), N-tertbutoxycarbonylamido (N-Boc), and N-o-nitrobenzenesulfonamide (oNs)] were prepared in moderate to good yield and with high enantiomeric excess of both isomers starting from N-protected imines, using a sulfonium salt derived from Eliel's oxathiane. The diastereoselectivities of the reactions are influenced by the imine N-protecting group, the imine substituent, and the sulfide structure. An unusual cis selectivity was observed in the formation of N-tosyl-2-phenyl-3-tert- butylaziridine and N-o-trimethylsilylethanesulfonamide-2-phenyl-3-tert- butylaziridine, which was explained by using computational models. The analysis suggests that betaine formation in the case of N-tosyl-tert-butylaldimine aziridination using oxathiane benzyl sulfonium ylide 1′ is reversible and that the selectivity is determined at the rotation step, which is unusual for semistabilized ylide aziridination. We have shown herein that the steric bulk of an imine substituent, in combination with a sterically demanding sulfonium ylide, can also affect the reversibility of the reaction. This is the first example of this sort involving aziridinations using semistabilized ylides.
- Dokli, Irena,Matanovic, Ivana,Hamersak, Zdenko
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scheme or table
p. 11744 - 11752
(2010/11/18)
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- Enhancing the solubility for hypervalent ortho-sulfonyl iodine compounds
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The synthesis and characterization of new hypervalent iodine reagents ArINTs (2a), ArIO (3a), and ArIO2 (4a) (Ar=2-tert-butylsulfonyl-5- tert-butylphenyl) are described. These reagents are compared to previously reported analogous set of reagen
- Meprathu, Bindu V.,Protasiewicz, John D.
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experimental part
p. 5768 - 5774
(2010/10/01)
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- PhI(OAc)2/I2 induced aziridination of alkenes with TsNH2 under mild conditions
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The aziridination of alkenes with the direct use of p-toluenesulfonamide (TsNH2) was achieved by using PhI(OAc)2 and I2 under mild conditions. The reaction affords aziridines in moderate to good yields, and offers good man
- Fan, Renhua,Pu, Dongming,Gan, Jianhong,Wang, Bing
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p. 4925 - 4928
(2008/09/21)
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- Iron-catalyzed aziridination reactions
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A small quantity of iron(II) triflate (2.5 to 5 mol%) catalyzes the aziridination reactions of enol silyl ethers with tosylimino(iodo)benzene (PhINTs) in acetonitrile to give α-N-tosylamido ketones by subsequent aziridine ring opening. Olefins are convert
- Nakanishi, Masafumi,Salit, Anne-Frederique,Bolm, Carsten
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scheme or table
p. 1835 - 1840
(2009/07/09)
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- Syntheses of acetonitrile ligated copper complexes with perfluoroalkoxy aluminate as counter anion and their catalytic application for olefin aziridination
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Acetonitrile ligated copper complexes with perfluoroalkoxy aluminate Al {OC (CF3)3}4- as weakly coordinating counter anion are successfully synthesized. Aziridination of various olefins with PhINTs catalyzed by
- Li, Yang,Diebl, Bernd,Raith, Alexander,Kühn, Fritz E.
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supporting information; body text
p. 5954 - 5956
(2009/04/11)
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- Palladium-catalyzed aziridination of alkenes using N,N-dichloro-p-toluenesulfonamide as nitrogen source
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N,N-Dichloro-p-toluenesulfonamide (TsNCl2) was found to be an efficient nitrogen source for the aziridination of unfunctionalized alkenes using palladium catalysts. Among the palladium salts, palladium acetate was the most effective catalyst for this reaction. A variety of alkenes were reacted at room temperature with TsNCl2 to form the desired aziridines in moderate to good yields. This method can complement our previous protocol which is limited to the use of electron-deficient α,β-unsaturated alkenes.
- Han, Jianlin,Li, Yufeng,Zhi, Sanjun,Pan, Yi,Timmons, Cody,Li, Guigen
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p. 7225 - 7228
(2007/10/03)
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- The first example of catalytic aziridination mediated by arsonium ylides: Preparation of trans-pentafluorophenyl-containing aziridines
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Triphenylarsine catalyzes the formation of aziridines from tosyl imines and aromatic diazo compounds in a one-pot reaction. It is the first example of catalytic aziridination mediated by arsonium ylides. It gave aziridines in excellent diastereoselectivity with pentafluorophenyl diazomethane as the substrate. This catalytic reaction is complementary with the reaction mediated by sulfur ylides. Georg Thieme Verlag Stuttgart.
- Zhu, Shifa,Liao, Yuanxi,Zhu, Shizheng
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p. 1429 - 1432
(2007/10/03)
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- Cobalt-catalyzed efficient aziridination of alkenes
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(Chemical Equation Presented) Cobalt porphyrins are capable of catalyzing the aziridination of alkenes with bromamine-T as the nitrene source. Among cobalt complexes of different porphyrins, Co(TDCIPP) is an effective catalyst that can aziridinate a wide
- Gao, Guang-Yao,Harden, Jeremiah D.,Zhang, X. Peter
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p. 3191 - 3193
(2007/10/03)
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- Iron(III) porphyrin catalyzed aziridination of alkenes with bromamine-T as nitrene source
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Equation presented. Iron(III) porphyrin complexes Fe(Por)Cl are effective catalysts for aziridination of alkenes using bromamine-T as the nitrene source. The catalytic system can operate under mild conditions with alkenes as limiting reagents. The aziridi
- Vyas, Renu,Gao, Guang-Yao,Harden, Jeremiah D.,Zhang, X. Peter
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p. 1907 - 1910
(2007/10/03)
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- N-bromoamides as versatile catalysts for aziridination of olefins using chloramine-T
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N-Bromoamides catalyze effectively the aziridination of electron-deficient as well as electron-rich olefins using chloramine-T (N-chloro-N-sodio-p-toluenesulfonamide) as a nitrogen source under ambient conditions to afford the corresponding aziridines in
- Thakur, Vinay V.,Sudalai
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p. 989 - 992
(2007/10/03)
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- Efficient Aziridination of Olefins Catalyzed by a Unique Disilver(I) Compound
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A unique disilver(I) compound is an efficient catalyst for aziridination of olefins. Copyright
- Cui, Yong,He, Chuan
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p. 16202 - 16203
(2007/10/03)
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- Microencapsulated Cu(acac)2: A recoverable and reusable polymer-supported copper catalyst for aziridination of olefins
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Microencapsulated copper(II) acetylacetonate was prepared and used in the aziridination of alkenes employing [N-(p-tolylsulfonyl)imino]phenyliodinane (PhI=NTs) as the nitrogen source. Microencapsulated copper(II) acetylacetonate [MC-Cu(acac)2] catalyst was reused for several cycles with consistent activity.
- Lakshmi Kantam,Kavita,Neeraja,Haritha,Chaudhuri,Dehury
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p. 9029 - 9032
(2007/10/03)
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- Aziridination of alkenes and amidation of alkanes by bis(tosylimido)ruthenium(VI) porphyrins. A mechanistic study
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Bis(tosylimido)ruthenium(VI) porphyrins, [Ru(VI)(Por)(NTs)2] (Por = TPP, TTP, 4-C1-TPP, 4-MeOTPP, OEP), were prepared in 60-74% yields by treatment of [Ru(II)(Por)(CO)(MeOH)] with (N-(p-tolylsulfonyl)- imino)phenyliodinane (PhI=NTS) in dichloromethane. In dichloromethane containing pyrazole, they reacted with alkenes or alkanes to give tosylamidoruthenium(IV) porphyrins, [Ru(IV)(Por)(NHTs)(pz)], in about 75% yields. The reactions of [Ru(VI)(TPP)(NTs)2] and [Ru(VI)(OEP)(NTs)2] with styrene, para-substituted styrenes, norbornene, cyclooctene, and β- methylstyrene afforded the corresponding N-tosylaziridines in 66-85% yields. The aziridination of cis-stilbene and cis-β-methylstyrene by [Ru(VI)(Por)(NTs)2] is nonstereospecific with a partial loss of the alkene stereochemistry. Kinetic studies on the reactions between [Ru(VI)(TPP)(NTs)2] and 16 alkenes (cyclooctene, norbornene, 2,3-dimethyl-2- butene, styrene, para-substituted styrenes, α and β-methylstyrene, and α- and β-deuteriostyrene) gave the second-order rate constants (k2) ranging from (1.60 ± 0.06) x 10-3 to (90 ± 4) x 10-3 dm3 mo1-1 s-1 at 298 K. The slope of the linear plot of log k2 vs E(l/2) for eight representative alkenes was found to be -1.7 V-1. In the case of para-substituted styrenes, linear correlation between log k(R) (k(R) = relative rate) and σ+ gives a ρ+ value as small as -1.1. However, the effect of para substituents on k(R) can be best accounted for by considering both the polar and spin delocalization effect. Measurements on the secondary deuterium isotope effect revealed that only the β-carbon atom of styrene experienced a significant change in its hybridization in reaching the transition state. All these are consistent with rate-determining formation of a carboradical intermediate. The reactions of [Ru(VI)(TPP)(NTs)2] and [Ru(VI-) (OEP)(NTs)2] with adamantane, cyclohexene, ethylbenzene, and cumene resulted in tosylamidation of these hydrocarbons and afforded the corresponding amides in 52-88% yields. For cyclohexane and toluene, the tosylamidation products were formed in poor yields (ca. 10%). Kinetic studies on the reactions between [Ru(VI-) (TPP)(NTs)2] and nine hydrocarbons (cumene, ethylbenzene, cyclohexene, and para-substituted ethylbenzenes) gave the second-order rate constants (k2) in the range of (0.330 ± 0.008) x 10-3 to (16.5 ± 0.3) x 10-3 dm3 mol-1 s-1. These reactions exhibit a large primary deuterium isotope effect, with a k(H)/k(D) ratio of 11 for the tosylamidation of ethylbenzene. In the case of para-substituted ethylbenzenes, both electron-donating and -withdrawing substituents moderately promote the reaction. There is an excellent linear correlation between log k(R) and a related carboradical parameter. On the basis of these observations, a mechanism involving the rate-limiting formation of a carboradical intermediate is postulated.
- Au, Sze-Man,Huang, Jie-Sheng,Yu, Wing-Yiu,Fung, Wai-Hong,Che, Chi-Ming
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p. 9120 - 9132
(2007/10/03)
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- Pyridinium hydrobromide perbromide: A versatile catalyst for aziridination of olefins using chloramine-T
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Formula presented Pyridinium hydrobromide perbromide (PyHBr3) catalyzes effectively the aziridination of electron-deficient as well as electron-rich olefins using Chloramine-T (N-chloro-N-sodio-p-toluenesulfonamide) as a nitrogen source to afford the corr
- Ali, Sayyed Iliyas,Nikalje, Milind D.,Sudalai
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p. 705 - 707
(2008/02/12)
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- Catalytic asymmetric heterogeneous aziridination of alkenes using zeolite CuHY with [N-(p-tolylsulfonyl)imino]phenyliodinane as nitrene donor
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Copper-exchanged zeolite Y (CuHY) is found to be a highly effective heterogeneous catalyst for the aziridination of alkenes using [N-(p-tolylsulfonyl)imino]phenyliodinane (PhI=NTs) as the nitrogen source. Exchange of zeolite Y with other cations (Ag+
- Langham, Christopher,Taylor, Sophia,Bethell, Donald,McMorn, Paul,Bulman Page, Philip C.,Willock, David J.,Sly, Chris,Hancock, Frederick E.,King, Frank,Hutchings, Graham J.
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p. 1043 - 1049
(2007/10/03)
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- Cleavage of sulfonamides with phenyldimethylsilyllithium
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The toluene-p-sulfonamides of secondary amines and indoles are cleaved by treatment with phenyldimethylsilyllithium to give the secondary amines. Aziridine toluene-p-sulfonamides, however, are opened by attack of the silyllithium reagent on carbon to give β-silylethyl sulfonamides. The aziridine toluene-p-sulfonamide 22 derived from norbornene is different in giving the 2-[dimethyl(phenyl)silyl]-4-methylbenzenesulfonamide 23 of exo-norbornylamine. The aziridine toluene-p-sulfonamides 26, 28 and 30, derived from methyl cinnamate, methyl acrylate and cinnamyl acetate, are also anomalous, giving 3-[N-(p-tolylsulfonyl)amino]-3-phenylpropionic acid 27, {3-[N-(p-tolylsulfonyl)amino]propionyl}-dimethyl(phenyl)silane 29 and trans-cinnamyl alcohol 31, respectively, each derived by opening of the aziridine ring followed by loss of the silyl group.
- Fleming, Ian,Frackenpohl, Jens,Ila, Hiriyakkanavar
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p. 1229 - 1235
(2007/10/03)
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- Catalytic and asymmetric aziridination using sulfur ylides
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This paper describes a new method for the preparation of aziridines from imines and diazocompounds which requires catalytic amounts of metal salts and sulfides and operates under neutral conditions. Using enantiomerically pure sulfides, high enantioselect
- Aggarwal, Varinder K.,Thompson, Alison,Jones, Ray V. H.,Standen, Mike C. H.
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p. 361 - 362
(2007/10/03)
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- Process for the preparation of an oxirane, azirdine or cyclopropane
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A process for the preparation of an oxirane, aziridine or cyclopropane of formula (I) wherein, X is oxygen, NR4 or CHR5 ; R1 is hydrogen, alkyl, aryl, heteroaromatic, heterocyclic or cycloalkyl; R2 is hydrogen, alkyl, aryl, heteroaromatic, CO2 R8, CHR14 NHR13, heterocyclic or cycloalkyl; or R1 and R2 join together to form a cycloalkyl ring; R3 is hydrogen, alkyl, aryl, heteroaromatic, CO2 R8, R83 Sn, CONR8 R9 or trimethylsilyl; R4 and R5 are, independently, alkyl, cycloalkyl, aryl, heteroaromatic, SO2 R8, SO3 R8, COR8, CO2 R8, CONR8 R9 or CN, or R4 can also be P(O)(aryl)2 ; R8 and R9 are independently alkyl, aryl or arylalkyl; R13 and R14 are independently hydrogen, alkyl or aryl; the process comprising reacting a mixture of a compound of formula (II), wherein R1, R2 and X are as defined above, and a sulphide of formula SR6 R7, wherein R6 and R7 are independently alkyl, aryl or heteroaomatic, or R6 and R7 join together to form a cycloalkyl ring which optionally includes an additional heteroatom, with either (i) a metallocarbon obtainable by reacting an alkylmetal with a methane derivative of formula CHR3 X'X", wherein R3 is as defined above, and X' and X" are independently, a leaving group, or (ii) a metallocarbon obtainable by reacting a compound of formula (III), (wherein R3 may not be hydrogen) with a suitable organometallic or inorganic reagent.
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- A NOVEL CATALYTIC CYCLE FOR THE SYNTHESIS OF EPOXIDES USING SULFUR YLIDES, AND APPLICATION TO THE SYNTHESIS OF CYCLOPROPANES AND AZIRIDINES.
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We have developed a new catalytic cycle for the synthesis of epoxides from carbonyl compounds and diazocompounds.These reactions are mediated by catalytic quantities of rhodium acetate (0.01 eq.) and dimethyl sulfide (0.2 eq.).In this catalytic cycle, phenyl diazomethane is decomposed by rhodium acetate to give a metallocarbene and this reacts with the sulfide to give a sulfur ylide which in turn reacts with the aldehyde to give an epoxide and returns the sulfide back into the catalytic cycle.The use of catalytic amounts of chiral sulfides gives non-racemic epoxides.It has been found that other diazocompounds can be used in the catalytic cycle e.g.N,N-diethyl diazoacetamide.In addition, it has been found that substitution of aldehydes for enones furnishes cyclopropanes, and substitution with imines gives aziridines.For the preparation of terminal epoxides, diazomethane could not be used instead of phenyl diazomethane.Instead, it was discovered that terminal epoxides could be prepared using diethyl zinc, chloroiodomethane, dimethyl sulfide and an aldehyde.A second catalytic cycle for epoxidation has therefore been developed.Key Words catalytic, asymmetric synthesis, sulfur ylide, epoxide, aziridine, cyclopropane, rhodium acetate, Simmons Smith.
- Aggarwal, Varinder K.,Abdel-Rahman, Hesham,Thompson, Alison,Mattison, Beverley,Jones, Ray V. H.
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p. 283 - 292
(2007/10/02)
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- Development of the copper-catalyzed olefin aziridination reaction
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Soluble Cu(I) and Cu(II) triflate and perchlorate salts are efficient catalysts for the aziridination of olefins employing (N-(p-tolylsulfonyl)imino)phenyliodinane, PhI=NTs, as the nitrene precursor. Electron-rich as well as electron-deficient olefins und
- Evans, David A.,Faul, Margaret M.,Bilodeau, Mark T.
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p. 2742 - 2753
(2007/10/02)
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- Copper-Catalyzed Aziridination of Olefins by (N-(p-Toluenesulfonyl)imino)phenyliodinane
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The Cu(I)- or Cu(II)-catalyzed aziridination of both electron-rich and electron-deficient olefins employing (N-(p-toluenesulfonyl)imino)phenyliodinane, PhI=NTs, as the nitrene precursor, affords N-tosylaziridines in yields ranging between 55percent - 95pe
- Evans, David A.,Faul, Margaret M.,Bilodeau, Mark T.
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p. 6744 - 6746
(2007/10/02)
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- REACTION OF DIMETHYLOXOSULFONIUM METHYLIDE WITH N-ARYLSULFONYLAZIRIDINES - STEREOSPECIFIC CONVERSION OF N-ARYLSULFONYLAZIRIDINES TO N-ARYLSULFONYLAZETIDINES
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Reaction of N-arylsulfonylaziridines with dimethyloxosulfonium methylide leads to the corresponding azetidines stereospecifically ; the cis-aziridines yielding the trans-azetidines and the trans-aziridines furnishing the cis-azetidines.This stereochemical course is interpreted in terms of an SN2-1,4-elimination mechanism.
- Nadir, Upender K.,Sharma, Raman L.,Koul, Veerinder K.
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p. 1851 - 1858
(2007/10/02)
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- Aziridination of Alkenes catalysed by Porphyrinirons: Selection of Catalysts for Optimal Efficiency and Stereospecificity
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meso-Tetra-arylporphyriniron(III) derivatives catalyse the N-tosylaziridination of aryl-substituted styrenes by tosylimidoiodobenzene, PhINTs, a nitrogen analogue of iodosylbenzene.Three secondary reactions were found to limit the yield of N-tosylaziridination: (i) the formation of toluene-p-sulphonamide, TsNH2, which is presumably derived from hydrolysis of a possible iron-nitrene, Fe=NTs, intermediate, (ii) the conversion of the Fe(TPP)(Cl) (TPP = tetraphenylporphyrin) catalyst into an iron(III) complex where the NTs moiety is inserted into an iron-nitrogen bond of Fe(TPP)(Cl), (iii) an oxidative degradation of the porphyrin catalyst.These secondary reactions were avoided to a great extent by using anhydrous conditions and Fe(TDCPP)(ClO4) (TDCPP = tetrakis-2,6-dichlorophenylporphyrin) as a catalyst instead of Fe(TPP)(Cl) and Fe(TPP)(ClO4).Under these conditions, N-tosylaziridination of styrene, cis- and trans-stilbene, and 1,1-diphenylethylene was performed with yields between 40 and 90percent.Fe(TDCPP)(ClO4) was also found to be the best catalyst for N-tosylaziridination of aliphatic alkenes such as hex-1-ene, cyclo-octene, and cis- and trans-hex-2-enes.Although N-tosylaziridination of the two latter alkenes catalysed by Fe(TPP)(Cl) was not stereospecific, this reaction became stereospecific with Fe(TDCPP)(ClO4) as catalyst.These results show that by a proper choice of the porphyriniron catalyst, relatively good yields of N-tosylaziridination of alkenes by PhINTs can be obtained.As for 1,2-disubstituted aliphatic alkenes, syn addition of the NTs moiety to the double bond takes place.A possible mechanism is presented.
- Mahy, Jean-Pierre,Bedi, Gustave,Battioni, Pierrette,Mansuy, Daniel
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p. 1517 - 1524
(2007/10/02)
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- Iron- and Manganese-porphyrin Catalysed Aziridination of Alkenes by Tosyl- and Acyl-iminoiodobenzene
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N-Substituted aziridines are formed by Fe- or Mn-porphyrin catalysed reactions of PhI=NR compounds (R = tosyl or COCF3) with alkenes; the stereochemical characteristics of these reactions are very different from those of the analogous epoxidation of alkenes by PhI=O.
- Mansuy, Daniel,Mahy, Jean-Pierre,Dureault, Annie,Bedi, Gustave,Battioni, Pierrette
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p. 1161 - 1163
(2007/10/02)
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