- Copper N-Heterocyclic Carbene Complexes As Active Catalysts for the Synthesis of 2-Substituted Oxazolines from Nitriles and Aminoalcohols
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The reaction between nitriles and aminoalcohols to access 2-substituted oxazolines was investigated. Using copper-NHC complexes, various nitriles were successfully converted into the corresponding oxazolines, under milder and less wasteful conditions than those of previously reported methods.
- Trose, Michael,Lazreg, Fa?ma,Lesieur, Mathieu,Cazin, Catherine S. J.
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p. 9910 - 9914
(2015/11/03)
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- Catalytic hydroamination of unactivated olefins using a Co catalyst for complex molecule synthesis
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Functional group tolerance is one of the important requirements for chemical reactions, especially for the synthesis of complex molecules. Herein, we report a mild, general, and functional group tolerant intramolecular hydroamination of unactivated olefins using a Co(salen) complex, an N-fluoropyridinium salt, and a disiloxane reagent. This method, which was carried out at room temperature (or 0 °C), afforded three-, five-, six-, and seven-membered ring nitrogen-containing heterocyclic compounds and was compatible with diverse functional groups.
- Shigehisa, Hiroki,Koseki, Natsumi,Shimizu, Nao,Fujisawa, Mayu,Niitsu, Makoto,Hiroya, Kou
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supporting information
p. 13534 - 13537
(2015/02/02)
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- Transition metal and base free synthesis of 2-aryl-2-oxazolines from aldehydes and β-amino alcohols catalysed by potassium iodide
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Synthesis of 2-aryl-2-oxazolines from β-amino alcohols and aldehydes was achieved in good to excellent yield by employing a potassium iodide (KI)-tert-butyl hydroperoxide (TBHP) catalytic system. This protocol is very mild, metal and base free and can be performed under ambient reaction conditions. This oxidative cyclization strategy was further extended for the synthesis of optically active 2-oxazolines, which can act as very useful chiral auxiliaries and as ligands. This journal is
- Uma Maheswari,Sathish Kumar,Venkateshwar
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p. 39897 - 39900
(2015/02/18)
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- Regioselectivity in Nucleophilic Ring Opening of 2-Methylaziridines. Lag of Bond Making as Model for the Abnormal Opening
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The regioselectivity ratio RS=normal:abnormal opening of activated 2-methylaziridines 2 by nucleophiles is found to range from 0.10 to unmeasurable large (only normal opening=substitution at CH2 by strongly basic carbanions).RS is assumed to result from SN2 variants differing in the degree to which bond breaking is ahead of bond making including perhaps synchronous SN2.Bond breaking will be more ahead for the N-CMe bond.High nucleophilic power pushes bond making toward a synchronous process resulting in great RS.The decrease in RS with acyl activation relative to sulfonyl activation is in accord with a flattening of the nitrogen pyramid (planarization effect).The planarization effect is retained in acidic medium by O-protonation: RS 0.10-0.14 for methanolysis as compared to RS 0.43 for N-protonated sulfonylaziridine 2h.AM1 calculations support the planarization hypothesis. - No indication for SET with trityl anion was found.
- Lin, Pen-Yuan,Bentz, Gunther,Stamm, Helmut
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- Organoselenium- and Proton-Mediated Cyclization Reactions of Allylic Amides and Thioamides. Syntheses of 2-Oxazolines and 2-Thiazolines
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A variety of allylic amides and thioamides were treated with phenylselenenyl bromide in chloroform to give, via 5-exo cyclization, 2-oxazolines and 2-thiazolines, respectively, carrying a (phenylselenenyl)methyl substituent in the 5-position.In some cases (N-crotyl- and N-cinnamylamides/thioamides), dihydro-1,3-oxazines/-thiazines were formed via 6-endo cyclization.The phenylselenenyl group of the cyclofunctionalization products was slowly eliminated by treatment with m-chloroperbenzoic acid to introduce unsaturation in the resulting oxazoline/thiazoline.Reductive removal of the phenylselenenyl group was effected by treatment with triphenyltin hydride.This reaction was sometimes accompanied by a rearrangement of the heterocyclic ring.Proton-induced cyclizations of allylic thioamides to give 2-thiazolines was slowly but efficiently effected in boiling toluene containing a catalytic amount of p-toluenesulfonic acid.
- Engman, Lars
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p. 3425 - 3430
(2007/10/02)
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- The Conversion of an Aziridine to a β-Lactam
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A one-pot, inert atmosphere conversion of an aziridine to a β-lactam using nickel tetracarbonyl as the carbonyl source is described.In this reaction it is the less substituted carbon-nitrogen bond which is carbonylated.The proposed mechanism for this reac
- Chamchaang, Wilaiporn,Pinhas, Allan R.
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p. 2943 - 2950
(2007/10/02)
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- Allenes. Part 44. Formation of Oxazolines and Benzoxazoles from Allenic nitriles and amides and from Phenylpropynenitrile.
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Michael addition of ethanolamines and 2-aminophenol to allenic nitriles, allenic amides and phenylpropynenitrile gives enaminic nitriles and amides which at 290 deg - 320 deg yield oxazolines and benzoxazoles.
- Fomum, Z. Tanee,Nkengfack, A. Ephrem,Mpango, George W. P.,Landor, Stephen R.,Landor, Phyllis D.
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p. 901 - 924
(2007/10/02)
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- Ring Opening of Aziridines by Different Fluorinating Reagents: Three Synthetic Routes to α,β-Fluoro Amines with Different Stereochemical Pathways
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The syntheses of α,β-fluoro amines from the reaction of secondary aziridines with either Olah's reagent (HF, pyridine) or anhydrous hydrogen fluoride and of N-activated aziridines with partially neutralized Olah's reagent (NR3-nHF) are reported.The stereo
- Alvernhe, Gerald M.,Ennakoua, Christine M.,Lacombe, Sylvie M.,Laurent, Andre J.
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p. 4938 - 4948
(2007/10/02)
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- SYNTHESE D'α,β-FLUOROAMINES A PARTIR D'AZIRIDINES: ORIENTATION DE L'OUVERTURE DU CYCLE ET AMELIORATION DU POUVOIR FLUORANT DU REACTIF DE OLAH
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Ring opening of aliphatic and aromatic aziridines by addition of Olah's reagent has ben studied.Yields and regioselectivity are improved when using the corresponding N-activated aziridines and less acidic fluorinating reagents obtained by addition of trie
- Alvernhe, Gerard,Lacombe, Sylvie,Laurent, Andre
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p. 289 - 292
(2007/10/02)
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