Umsetzungen von Dilithio‐nitroalkanen und ‐allylnitroderivaten mit Carbonylverbindungen

Lehr, Friedrich; Gonnermann, Jutta; Seebàch, Dieter

doi:10.1002/hlca.19790620722

Cited by 54 publications

(16 citation statements)

References 36 publications

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“…N ‐Hydroxy Amino Acid Ester 10: From methyl 2‐bromo‐2‐phenylacetate (5.249 g, 22.91 mmol), acetaldoxime (1.301 g, 22.03 mmol), sodium (0.507 g, 22.03 mmol) and hydroxylamine hydrochloride (1.531 g, 22.03 mmol), compound 10 (1.275 g, 7.04 mmol, 32 %) was obtained as a white solid. The analytic data match the values reported in the literature 55. M.p.…”

Section: Methodssupporting

confidence: 87%

Stabilizing Factors for Vanadium(IV) in Amavadin

2007

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Keywords: Amavadin / Vanadium / Reductive hydroxylamination / Hydroxylamines / Nitrones / Mass spectrometry Six secondary N-hydroxy amino acids (amavadin-based ligands) have been prepared through a strategy with nitrone reduction as its key step. Two of these amino acids are the new amavadin ligand analogues 4a and 4b containing either a phenyl or a benzyl group in combination with a small backbone substituent. In addition, the monoester 5 of the amavadin ligand as well as three N-alkylated N-hydroxy amino acids 6 were prepared. Complexation studies with the new tri-and bidentate ligands using HRMS revealed that only

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Section: Methodssupporting

confidence: 87%

Stabilizing Factors for Vanadium(IV) in Amavadin

2007

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“…-I3C-NMR. (Acetond6): 207,33 (C(13)); 88,92 (C(16)); 80,08 (C(1)); 53,60 (C(12)); 38,82,35,76,27,46,27,09,26,85,26,57,24,34,23,76,23,33,21,24 und 19,. -MS.: 297 (10, M t , C1&7N04), 279 (5), 267 (7), 249 (13), 221 (3), 209 (24), 182 (5), 173 (9), 158 (13), 139 (9) C16H27N04 (297,40) Ber.…”

Section: -Methyl-5-nitro-bicyclo[44o]decan-2-onmentioning

confidence: 99%

3‐Hydroxy‐4‐nitro‐cyclohexanone aus Ketonen und 4‐Nitrobuttersäurechlorid. Eine ringerweiternde Fünfringanellierung

Weller

Seebàch²,

Davis

et al. 1981

Helvetica Chimica Acta

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The 6-nitro-1,3-diketones 5, 8, 9, 10, and 11, prepared by a 1: 1 acylation at the C-atom of non-hindered lithium enolates with 4-nitrobutanoyl chloride according to equation 3, are cyclized with sodium hydrogen carbonate in aqueous tetrahydrofuran to give the hydroxy-nitro-ketones 13-17. Such cyclicnitroaldols are not formed from the cyclopentanone, -heptanone, and -octanone, nor from the aryl derivatives 4,6,7 and 12, respectively. Except for the vicinally trisubstituted compound 14, the cyclization products are isolated in diastereomerically pure form. A crystal structure X-ray analysis reveals the trans-decalone and the cis-D-nitroalcohol configurations of the product 13 from cyclohexanone (see Fig. 1-3). Acetalization to 21-25 and catalytic hydrogenation of the nitro groups furnishes the amino alcohols 27-31 (Table 4 ) which are substrates for the Tiffeneau-Demjanow rearrangement (see Schemes 2, 3, 4 and 5). From the stereoelectronic control of this sextett rearrangement we deduce the configurations of the 1,Cdiketones 35, 36, 39, 40, 43, 44, 46, and 47 formed under kinetic or thermodynamic conditions. The six-ring annulation with nitrobutanoic acid and the subsequent rearrangement are shown in Scheme 6; the sequence of reactions described here allows to carry out a ring enlargement of a cyclic ketone by one C-atom, with simultaneous annulation of a cyclopentanone ring. 1. Einleitung. -Die vielseitige Verwendbarkeit aliphatischer Nitroverbindungen in der synthetischen organischen Chemie kann heute kaum mehr ubersehen werden [ 11 [2]. Dies beruht vor allem darauf, dass Nitroaliphaten als Reagentien mit umgepolter Reaktivitat [2] [3] eingesetzt werden konnen. Die Nutzlichkeit von 3-Nitropropionsaure-und 3-Nitroacrylsaurederivaten als Carbonyl-d3-[3-51 und I ) *) Korrespondenzautor. Die vorliegende Arbeit ist Teil der geplanten Dissertation von T. W., ETH Zurich. 1 3 Carbonyl-a2-Reagentien [6] sowie zur Erzielung regioselektiver Diels-AZder-Reaktionen [7] wurde kiirzlich aufgezeigt. Wie in Schema I dargestellt, lassen sich infolge spontaner HN02-Eliminierung in zwei Reaktionsschritten substituierte Hydroxycyclopentenone vom Typ 1 synthetisieren (Schema 1, Weg A). Stellt diese Sequenz eine einfache Fiinfring-Anellierungsmethode dar, so sollte in Analogie dazu mit 4-Nitrobutyrylchlorid eine entsprechende Sechsring-Cyclisierungsvariante moglich sein (Schema 1, Weg C ) . Dadurch wiirde man zu ahnlich substituierten Produkten gelangen, wie sie bereits durch Addition und anschliessende Cyclisierung von doppelt metallierten 2-Acetylcycloalkanonen an o-Nitrostyrole erhalten wurden [8] (Schema I , Weg B, 2). Ziel der vorliegenden Arbeit war es auch, die Anellierungsprodukte vom Typ 3 durch Reduktion der Nitrogruppe in nitrofreie Verbindungen umzuwandeln. Die in Schema 1 (Weg C ) dargestellte Sequenz wiirde demnach eine weitere '4nwendung von 4-Nitrobuttersaurederivaten als C4-Bausteinen zur Synthese von substituierten Sechsringen darstellen (vgl. die Umsetzungen in Gleichung 1 [9] und 2 [ 101). 2. Acylierungsreaktianen....

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“…30,31 Given the well-established configurational stability of Boc-protected a-amino aldehydes, we chose to prepare three representative alkenes 9a-c (R = Me, PhCH 2 , Ph) from the corresponding Boc-protected aldehydes 10a-c and (p-tolylthio)nitromethane 11 by the two-pot Henry reaction/elimination process [34][35][36] that we had employed successfully for the synthesis of the corresponding protected 3-hydroxy l-arylthio-l-nitroalkenes. 30 In the case of the alkene 9a, the initial condensation was carried out using the dianion generated from (ptolylthio)nitromethane 11, 31,37,38 rather than by the use of the (presumed) monoanion generated using t-BuOKt-BuOH. Epoxidation of the alkenes 9a-c with t-BuOO-Li, 39 followed by normal work-up and flash chromatography led not to the expected epoxides 12a-c, but to high yields of the corresponding cis-oxazolidinones 13a-c, respectively (Scheme 2).…”

Section: Synthesis Of Anti-a-amino-b-hydroxy Acidsmentioning

confidence: 99%

Stereocontrolled Synthesis ofanti-α-Hydroxy-β-Amino andanti-α,β-Diamino Acid Derivatives by Epoxidation of 1-Arylthio-1-nitroalkenes

Ambroise¹,

Dumez²,

Szeki³

et al. 2002

Synthesis

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Stereocontrolled Synthesis of anti-a-Hydroxy-b-Amino and anti-a,b-DiaminoAcid Derivatives by Epoxidation of 1-Arylthio-1-nitroalkenes S t e r e o c o n t r o l l e d S y n t h e s i s o f a n t ia-Hydroxy-b-Amino a n d a n t ia,b-Diamino A c i d D e r i v a t i v e s Abstract: Epoxidation of 1-tolylthio-1-nitroalkenes containing an allylic Boc-protected amino group yields cis-oxazolidinones 13, formed by intramolecular trapping of the presumed intermediate epoxides by the carbamate group. Epoxidation of the analogous Z-or Fmoc-protected derivatives yields the corresponding syn-epoxides which, although they cannot be isolated, can be trapped with aqueous ammonia, or more efficiently benzylamine, to give stereoisomerically pure anti-a,b-diamino acid derivatives.

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Umsetzungen von Dilithio‐nitroalkanen und ‐allylnitroderivaten mit Carbonylverbindungen

Cited by 54 publications

References 36 publications

Stabilizing Factors for Vanadium(IV) in Amavadin

Stabilizing Factors for Vanadium(IV) in Amavadin

3‐Hydroxy‐4‐nitro‐cyclohexanone aus Ketonen und 4‐Nitrobuttersäurechlorid. Eine ringerweiternde Fünfringanellierung

Stereocontrolled Synthesis ofanti-α-Hydroxy-β-Amino andanti-α,β-Diamino Acid Derivatives by Epoxidation of 1-Arylthio-1-nitroalkenes

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