- Weak base-promoted selective rearrangement of oxaziridines to amidesviavisible-light photoredox catalysis
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The selective rearrangement of oxaziridines to amidesviaa single electron transfer (SET) pathway is unexplored. In this study, we present a weak base-promoted selective rearrangement of oxaziridines to amidesviavisible-light photoredox catalysis. The developed method shows excellent functional group tolerance with a broad substrate scope and good to excellent yields. Furthermore, control experiments and density functional theory (DFT) calculations are performed to gain insight into the reactivity and selectivity.
- Park, Jin,Park, Sehoon,Jang, Gwang Seok,Kim, Ran Hui,Jung, Jaehoon,Woo, Sang Kook
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supporting information
p. 9995 - 9998
(2021/10/06)
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- Atom economical synthesis of: N -alkylbenzamides via the iron(III) sulfate catalyzed rearrangement of 2-alkyl-3-aryloxaziridines in water and in the presence of a surfactant
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A green and mild synthetic route to N-alkylbenzamides involves eco-friendly one pot synthesis of 2-alkyl-3-aryloxaziridines from N-alkylamines and benzaldehydes followed by iron(iii) sulfate catalyzed rearrangement to the corresponding amides in water as the solvent and in the presence of sodium dodecyl sulfate as the surfactant. This green approach affords N-alkylbenzamides in high overall yields under simple and minimum manipulation.
- Kra?em, Jamil,Ollevier, Thierry
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supporting information
p. 1263 - 1267
(2017/08/15)
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- Hydrogen peroxide/dimethyl carbonate: A green system for epoxidation of: N -alkylimines and N -sulfonylimines. One-pot synthesis of N -alkyloxaziridines from N -alkylamines and (hetero)aromatic aldehydes
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A green method for epoxidation of imines using an environmentally benign oxidant system, H2O2/dimethyl carbonate, was developed. N-Alkyloxaziridines were prepared in high yields from N-alkylamines and (hetero)aromatic aldehydes in one-pot fashion, whereas N-sulfonyloxaziridines have been prepared by using the same oxidant system and 5 mol% of Zn(OAc)2·2H2O as catalyst.
- Kra?em, Jamil,Ghedira, Donia,Ollevier, Thierry
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p. 4859 - 4864
(2016/10/12)
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- UV-vis monitoring of radical polymerizations by spin trapping with chromophoric nitrones
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The application of chromophoric radical spin traps for highly sensitive UV-vis monitoring of conversion of radical enhanced spin capturing polymerizations (ESCP) is presented. In ESCP the growing macroradical is reacting with a nitrone providing the corresponding polymeric nitroxide radical spin trap which will react irreversibly with a second macroradical to eventually give a polymeric alkoxyamine. The progress of styrene and n-butyl acrylate ESC polymerizations in the presence of π-conjugated nitrones is successfully visualized via a significant change of absorbance of the nitrone chromophore in the 200-500 nm range due to the nitrone transformation into an alkoxyamine moiety upon incorporation into the polymer. Moreover, related studies on UV-vis monitoring of photochemical rearrangement of nitrones to their corresponding oxaziridines are discussed.
- Husmann, Ralph,Wertz, Sebastian,Daniliuc, Constantin G.,Schaefer, Sascha W.,McArdle, Ciaran B.,Studer, Armido
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p. 993 - 1000
(2014/03/21)
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- Synthesis of dihydrobenzisoxazoles by the [3 + 2] cycloaddition of arynes and oxaziridines
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Dihydrobenzisoxazoles are readily prepared in good yields by the [3 + 2] cycloaddition of oxaziridines and arynes. The reaction involves an unusual cleavage of the C-O bond of the oxaziridine and tolerates a variety of substituents on the oxaziridine and the o-(trimethylsilyl)aryl triflate to form aryl-, heteroaryl-, alkyl-, and naphthyl-substituted dihydrobenzisoxazoles. The resulting halogen-substituted dihydrobenzisoxazoles are readily elaborated to more complex products using palladium-catalyzed crossing-coupling processes.
- Kivrak, Arif,Larock, Richard C.
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supporting information; experimental part
p. 7381 - 7387
(2011/02/22)
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- trans-(±)-2-tert-butyl-3-phenyloxaziridine: A unique reagent for the oxidation of thiolates into sulfenates
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(Chemical Equation Presented) Aliphatic thiolates were efficiently converted into the corresponding sulfenates by smooth oxidation with trans-(±)-2-tert-butyl-3-phenyloxaziridine at room temperature (five examples). Subsequent electrophilic quench with benzyl bromide led to sulfoxides (S-alkylation) in good to moderate yields. Application of the protocol to an aromatic substrate was also successful. This work represents the first valuable example of the use of this poorly active oxidizing agent in synthetic organic chemistry without the need for activating conditions.
- Boudou, Cedric,Berges, Matthieu,Sagnes, Charlene,Sopkova-De Oliveira Santos, Jana,Perrio, Stephane,Metzner, Patrick
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p. 5403 - 5406
(2008/02/09)
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- [Bmim]BF4-immobilized rhenium-catalyzed highly efficient oxygenation of aldimines to oxaziridines using solid peroxides as oxidants
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Various rhenium-based catalysts immobilized in [bmim]BF4 were found to be efficient for oxygenation of various aldimines to the corresponding oxaziridines in excellent yields under mild conditions using solid peroxides like UHP, SPC and SPB as oxidants. Among the various rhenium-based catalysts studied, MTO was found to be most efficient. The reusability and recyclability of MTO immobilized in [bmim]BF4 was established by using it for three subsequent cycles for oxygenation of benzylidine-tert-butylamine using UHP as oxidant.
- Jain, Suman L.,Singhal, Sweety,Sain, Bir
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p. 2930 - 2935
(2008/02/02)
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- An environmentally friendly oxidation system for the selective oxygenation of aldimines to oxaziridines with anhydrous TBHP and alumina-supported MoO 3 as a recyclable heterogeneous catalyst
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A highly efficient and selective protocol for the oxygenation of various aldimines to oxaziridines, which proceeds in excellent yields with enhanced selectivity by using alumina-supported M0O3 as a recyclable heterogeneous catalyst and anhydrous TBHP as the ultimate oxidant, is described. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Singhal, Sweety,Jain, Suman L.,Prasad,Sain, Bir
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p. 2051 - 2054
(2008/02/04)
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- An inexpensive and selective oxygenation of N-alkyl imines to oxaziridines
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A range of N-alkyl imines was oxidised to corresponding oxaziridines in a highly selective manner with sodium tungstate-30% H2O2 in acetonitrile under mild conditions.
- Shailaja,Manjula,Rao, B. Vittal
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p. 1176 - 1178
(2007/10/03)
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- Simple and highly efficient synthesis of oxaziridines by tetrabutylammonium Oxone
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Oxygenation of various aldimines with tetrabutylammonium monoperoxysulfate produced the corresponding E- or a mixture of E- and Z-oxaziridines with very high yields (≥90%) and good to excellent selectivities (75-100%) within 20min to 10h in CH3CN at room temperature (~25°C). The E/Z isomer ratio critically depends on the stereo-electronic nature of the substituents in the oxaziridines, solvent, and the presence of Lewis acids and bases.
- Mohajer, Daryoush,Iranpoor, Nasser,Rezaeifard, Abdolreza
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p. 631 - 634
(2007/10/03)
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- Stereospecific synthesis of 2-alkyl-3-aryloxaziridines from prochiral and chiral N-arylidenealkylamines by use of the benzonitrile-hydrogen peroxide system
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Benzonitrile-hydrogen peroxide oxidation of prochiral and chiral imines 1a-h leads to racemic (E)-oxaziridines (R,R/S,S) and nonracemic (E)-oxaziridines (R,R,R/S,S,R) 2a-h, respectively.
- Kraiem,Kacem,Khiari,Ben Hassine
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p. 263 - 271
(2007/10/03)
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- Sulfonic peracids - III. Heteroatom oxidation and chemoselectivity
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We have investigated the p-toluenesulfonic peracid (2) generated in situ in the oxidation of different types of compounds containing nitrogen and/or sulfur. The sulfonic peracid 2 shows a remarkable chemoselectivity characterized by a preferred oxidation of sulfides to the sulfones in the presence of amines or olefins and a strong dependence on the nature of the amine in the competitive oxidation of olefins and amines.
- Kluge,Schulz,Liebsch
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p. 5773 - 5782
(2007/10/03)
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- PHASE-TRANSFER CATALYTIC SYNTHESIS OF OXAZIRIDINES
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The phase-transfer catalytic oxidation of imines is a general method for the preparation of oxaziridines with various structures.Oxone (2KHSO5*KHSO4*K2SO4) and perbenzoic acid in combination with such phase-transfer catalysts as benzyltriethylammonium chl
- Bulachkova, A. I.,Koldobskii, G. I.,Drozdetskii, A. G.,Tereshchenko, G. F.
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p. 632 - 636
(2007/10/02)
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- Imines and Derivatives. Part 24. Nitrone Synthesis by Imine Oxidation using either a Peroxyacid or Dimethyldioxirane
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The oxidation of N-alkyl imines by m-chloroperoxybenzoic acid to yield nitrones was facilitated by (i) the presence of C-aryl substituents, (ii) steric inhibition of attack at the imino C-atom, (iii) electron donating para-substituents on the C-aryl substituent, (iv) non-hydroxylic solvents, (v) optimal conjugation between C-aryl substituents and the imino group, and (vi) less bulky N-alkyl groups. The oxidation of N-alkyl imines by dimethyldioxirane (DMD) in dichloromethane-acetone solution yielded nitrones without evidence of oxaziridine formation.The yields of isolated nitrones were higher for C,C-diaryl imines and for imines bearing less bulky N-alkyl substituents.N-H substituted ketimines were found to yield oximes after reaction with dimethyldioxirane.
- Boyd, Derek R.,Coulter, Peter B.,McGuckin, M. Rosaleen,Sharma, Narain D.,Jennings, W. Brian,Wilson, Valerie E.
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p. 301 - 306
(2007/10/02)
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- Rearrangement Reactions of Oxaziridines to Nitrones. X-Ray Crystal and Molecular Structure of N-t-Butyl-α(o-hydroxyphenyl)nitrone
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Substituted N-benzylidene-t-butylamines are oxidized with m-chloroperoxybenzoic acid to oxaziridines which can rearrange to the corresponding nitrones when electron-donating groups are present in the phenyl ring.The oxaziridine-to-nitrone rearrangement, which has been considered as a 'pseudo-abnormal' reaction, can also be catalysed by Lewis acids.It has been found that the rearrangement of 2-t-butyl-3-(o-hydroxyphenyl)oxaziridine to the corresponding nitrone is of first order.The rearrangement has been investigated for different substituents in the phenyl ring, andin the case of 2-t-butyl-3-phenyloxaziridine substituted in the ortho position with electron-donating groups it has been found that the presence of protons of a Lewis acid is necessary.An X-ray structure of α-(o-hydroxyphenyl)-N-t-butylnitrone shows strong hydrogen bonding between the nitrone oxygen and the hydrogen in the hydroxy group.The oxaziridine-to-nitrone rearrangement is also analysed from a theoretical point of view using ab initio calculations.A Mulliken-population analysis of the C-O and N-O bonds in the oxaziridine ring for para-substitued 2-t-butyl-3-phenyloxaziridines shows a reduction of the C-O bond population when an electron-donating group is present in the para position of the phenyl ring compared with an electron-withdrawing group; the N-O bond populations show the reverse picture.A state-correlation diagram for the oxaziridine-to-nitrone rearrangement is also presented and the experimental and theoretical results support each other.
- Christensen, Dorthe,Jorgensen, Karl Anker,Hazell, Rita G.
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p. 2391 - 2397
(2007/10/02)
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- THE REACTIONS OF N-BENZOYLPEROXYCARBAMIC ACID WITH AZINES AND IMINES
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N-Benzoylperoxycarbamic acid (BPC) was found to react generally with imines and azines to form oxaziridines rather than N-oxides.The imine products were stable, but those found from azines apparently were unstable and converted to ketones or aldehydes plus diazo compounds.
- Paredes, Rodrigo,Bastos, Holger,Montoya, Raul,Chavez, Alba Lucia,Dolbier, William R.,Burkholder, Conrad R.
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p. 6821 - 6830
(2007/10/02)
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- DYNAMIC STEREOCHEMISTRY OF IMINES AND DERIVATIVES. PART 18. PHOTOSYNTHESIS AND PHOTORACEMIZATION OF OPTICALLY ACTIVE OXAZIRIDINES
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Optically active oxaziridines have been synthesized with a maximum optical yield of 31percent by photoisomerization (λ > 300 nm) of achiral aldo- and keto-nitrones in the presence of the chiral solvent (+)-(S) or (-)-(R)-2,2,2-trifluoro-1-phenylethanol.Ph
- Boyd, Derek R.,Campbell, Rose M.,Coulter, Peter B.,Grimshaw, James,Neill, David C.,Jennings, W. Brian
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p. 849 - 856
(2007/10/02)
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- NORMAL, ABNORMAL AND PSEUDO-ABNORMAL REACTION PATHWAYS FOR THE IMINE-PEROXYACID REACTION
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Steric and mesomeric effects have a marked influence upon the formation of oxaziridine (normal pathway) or nitrone (abnormal pathway) products from the imine-peroxyacid reaction; n.m.r. studies of the thermal isomerization of oxaziridines to nitrones prov
- Boyd, Derek R.,Coulter, Peter B.,Sharma, Narain D.,Jennings, Brian W.,Wilson, Valerie E.
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p. 1673 - 1676
(2007/10/02)
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- Oxygen Transfer fom Oxaziridines: A Chemical Model for Flavin-Dependent Monooxygenases
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The ability of several aryloxaziridines to transfer an oxygen atom to phenolates was examined. 2-(p-Nitrophenyl)-3-tert-butyloxaziridine (1) was found to oxidize potassium 2,6-dialkylphenolates to the corresponding p-benzoquinones.Product studies and an observed ESR signal suggest an electron-transfer mechanism for these oxidations. 18O-labeled oxaziridine 30 was prepared.Oxidations of phenolates with 30 rigorously establish the oxaziridine ring oxygen as the atom that is transferred to substrate.Kinetic studies with oxaziridine 1 and the isomeric nitrone 15 rule out the nitrone as an obligate intermediate in the oxygen-transfer reaction.In the oxidation of substrate, a single electron transfer from phenolate to oxaziridine is thought to generate a phenoxy/nitroxyl radical pair, which upon coupling and fragmentation achieves the oxygen transfer.These oxygen-transfer reactions serve as models for the proposed flavin-based oxaziridine 34 in enzyme-mediated monooxygenations.
- Wagner, William R.,Spero, Denice M.,Rastetter, William H.
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p. 1476 - 1480
(2007/10/02)
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- Autoxidation Reactions of Imines to form Oxaziridines and Amides
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The formation of oxaziridines and the isomeric amides in equal amounts by the spontaneous autoxidation of several liquid imines via peroxyimidic acid intermediates is reported.
- Auret, Barbara J.,Boyd, Derek R.,Coulter, Peter B.
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p. 463 - 464
(2007/10/02)
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