Aufbau neuer heterocyclen mittels intramolekularer nitron-olefin-cycloadditionen

Oppolzer, Wolfgang; Keller, Kathrin

doi:10.1016/s0040-4039(01)97923-7

Cited by 62 publications

(13 citation statements)

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“…Indeed, only a few compounds possessing the same bridged bicyclic dioxazepine skeleton have been synthesized previously through intramolecular dipolar cycloaddition of alkenyl [12] or allenyl nitrones.…”

Section: Resultsmentioning

confidence: 99%

Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

et al. 2003

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We have studied the cyclization of (4Z)-2,2,5,8,8-pentamethyl-4-nonene-3,7-dione (3E)-oxime (2). We have previously claimed the formation of a stable 3,5,5-trisubstituted 3-isoxazolidinol and of a bridged bicycle 4,5-dihydro-2,5-methano-1,4,3-dioxazepine in the reaction of 2 with hydrochloric acid in anhydrous diethyl ether. We report in this article that the above compounds are actually 3,3-dimethyl-1-(5Ј-tert-butyl-5Ј-hydroxy-3Ј-methylisoxazolidin-3Ј-yl)butan-2-one (5) and

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Section: Resultsmentioning

confidence: 99%

Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

et al. 2003

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“…In 1970, the first example of an intramolecular oxime olefin cycloaddition (IOOC) reaction was reported by Oppolzer and Keller. 1 Further examples of IOOC reactions have been reported by the groups of Wildman, 2 Grigg,3 Heathcock, 4 Hassner, 5 among others. 6 As part of a programme directed towards the synthesis of novel glycosidase inhibitors, we wished to determine whether IOOC reactions of carbohydrate derived precursors could be used to construct highly functionalised 3-oxa-2-azabicyclo[3.3.0]hexanes.…”

mentioning

confidence: 87%

Stereoselective Intramolecular Oxime Olefin Cycloadditions Involving Carbohydrate Derived Precursors

Moutel¹,

Shipman²

1998

Synlett

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Intramolecular oxime olefin cycloaddition reactions of carbohydrate derived precursors can be used to prepare highly functionalised 3-oxa-2-azabicyclo[3.3.0]hexanes with good to excellent levels of stereocontrol.In 1970, the first example of an intramolecular oxime olefin cycloaddition (IOOC) reaction was reported by Oppolzer and Keller. 1 Further examples of IOOC reactions have been reported by the groups of Wildman, 2 Grigg, 3 Heathcock, 4 Hassner, 5 among others. 6 As part of a programme directed towards the synthesis of novel glycosidase inhibitors, we wished to determine whether IOOC reactions of carbohydrate derived precursors could be used to construct highly functionalised 3-oxa-2-azabicyclo[3.3.0]hexanes. 7 Furthermore, while some of the previous work indicated that good levels of stereocontrol can be accomplished in relatively simple IOOC reactions, it was unclear at the outset of our studies whether good, predictable levels of stereocontrol could be accomplished in more complex systems. In this letter, we describe a series of stereoselective IOOC reactions using carbohydrate derived precursors and provide some insight into the factors which control the stereochemical outcome of these reactions.Our initial studies were conducted with oxime 1, which was prepared in 6 steps from methyl α-D-glucopyranoside using a Vasella fragmentation as the key step. 7a,b To our delight, thermolysis of this oxime in refluxing toluene for 15 hours produced bicycle 2 in quantitative yield as essentially a single stereoisomer as judged by NMR spectroscopy (Scheme 1). 8,9 Similar results were obtained using either pure (E)-1 or a mixture of (E)-1 and (Z)-1. The cis ring junction and relative stereochemical relationships within bicycle 2 were established using selective nOe difference measurements. 9 To account for the observed stereochemical outcome of this reaction, we suggest that after initial 1,2-prototropic shift, the cycloaddition proceeds with the oxime and olefin components in exo orientations and the benzyl ethers orientated in pseudo equatorial positions about the forming 5-membered ring. Scheme 1To test the generality of this reaction, and to probe the remarkable stereospecificity of this cycloaddition, we have undertaken several other related reactions using other oxime precursors (see Table 1). Oximes 3-6, derived from D-glucose, D-glucal, D-mannose and D-galactose respectively, all undergo intramolecular oxime olefin cycloadditions in good yields. Benzoate protected oxime 3 yielded cycloadduct 7 as the sole product (Table 1, Entry 1). In the other cases, two stereoisomeric cycloadducts were produced in varying proportions depending on the precise structure of the oxime substrate (Table 1, Entries 2-4). With the exception of 2-deoxyglucose series (Table 1, Entry 2), the stereochemistry of the products was elucidated using nOe difference measurements.Downloaded by: University of Arizona Library. Copyrighted material. LETTERS SYNLETTFrom these results, it would appear that the stereogenic centre adjacent to the ox...

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“…[38] Grigg and co-workers have developed an elegant three-component cascade process that allows these nitrone intermediates to be generated and cyclised in a single operation. Here, the catalytic π-allylpalladium species generated from the carbopalladation of allenes with aryl (or heteroaryl) iodides were captured by an external phenolic nucleophile 68 bearing the required nitrone moiety (Scheme 25).…”

Section: Carbopalladation Of Allenesmentioning

confidence: 99%

Pd‐Assisted Multicomponent Synthesis of Heterocycles

2003

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This review highlights some remarkable recently made achievements in the application of palladium‐mediated processes to the design of multicomponent one‐pot syntheses of heterocyclic compounds. Palladium‐catalysed cascade reactions are surveyed, together with processes based on sequential, one‐pot performance of individual transformations in which at least one is catalysed by palladium. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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Aufbau neuer heterocyclen mittels intramolekularer nitron-olefin-cycloadditionen

Cited by 62 publications

References 1 publication

Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

Stereoselective Intramolecular Oxime Olefin Cycloadditions Involving Carbohydrate Derived Precursors

Pd‐Assisted Multicomponent Synthesis of Heterocycles

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Aufbau neuer heterocyclen mittels intramolekularer nitron-olefin-cycloadditionen

Cited by 62 publications

References 1 publication

Correction to Withdrawn Article[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

Correction to Withdrawn Article[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

Stereoselective Intramolecular Oxime Olefin Cycloadditions Involving Carbohydrate Derived Precursors

Pd‐Assisted Multicomponent Synthesis of Heterocycles

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Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether

Correction to Withdrawn Article^[3,4] Cyclization Products of δ‐Oxo‐α,β‐unsaturated Ketoxime During Reaction with Hydrochloric Acid in Anhydrous Diethyl Ether