Ring Expansion Induced by DAST: Synthesis of Substituted 3‐Fluoropiperidines from Prolinols and 3‐Fluoroazepanes from 2‐Hydroxymethylpiperidines

Déchamps, Ingrid; Pardo, Domingo Gomez; Cossy, Janine

doi:10.1002/ejoc.200700237

Cited by 48 publications

(18 citation statements)

References 68 publications

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“…Such processes can lead to rearrangement, and this outcome has been rationally exploited to synthesise fluorinated five- [59], six- [60] and seven-membered [61] N -heterocycles that may have been otherwise difficult to access (e.g. 48 → 49 , Scheme 4).…”

Section: Reviewmentioning

confidence: 99%

Stereoselectively fluorinated N-heterocycles: a brief survey

Hu¹,

Hunter²

2013

Beilstein J. Org. Chem.

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SummaryThe stereoselective incorporation of fluorine atoms into N-heterocycles can lead to dramatic changes in the molecules’ physical and chemical properties. These changes can be rationally exploited for the benefit of diverse fields such as medicinal chemistry and organocatalysis. This brief review will examine some of the effects that fluorine substitution can have in N-heterocycles, including changes to the molecules’ stability, their conformational behaviour, their hydrogen bonding ability, and their basicity. Finally, some methods for the synthesis of stereoselectively fluorinated N-heterocycles will also be reviewed.

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Section: Reviewmentioning

confidence: 99%

Stereoselectively fluorinated N-heterocycles: a brief survey

Hu¹,

Hunter²

2013

Beilstein J. Org. Chem.

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“…The subsequent ring‐opening reactions will then generate cyclic products, thus rendering this a convenient approach toward the construction of different types of azaheterocyclic scaffolds (Scheme ). This approach of handling internal electrophiles within the aziridine side chain has found already applications in the synthesis of pyrrolidines and piperidines, as well as synthons of pharmaceutical products and alkaloids 6e…”

Section: Introductionmentioning

confidence: 99%

Nucleophile‐Dependent Regio‐ and Stereoselective Ring Opening of 1‐Azoniabicyclo[3.1.0]hexane Tosylate

Hertsen

Yoon

et al. 2014

Chemistry An Asian Journal

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1-[(1R)-(1-Phenylethyl)]-1-azoniabicyclo[3.1.0]hexane tosylate was generated as a stable bicyclic aziridinium salt from the corresponding 2-(3-hydroxypropyl)aziridine upon reaction with p-toluenesulfonyl anhydride. This bicyclic aziridinium ion was then treated with various nucleophiles including halides, azide, acetate, and cyanide in CH3CN to afford either piperidines or pyrrolidines through regio- and stereoselective ring opening, mediated by the characteristics of the applied nucleophile. On the basis of DFT calculations, ring-opening reactions under thermodynamic control yield piperidines, whereas reactions under kinetic control can yield both piperidines and pyrrolidines depending on the activation energies for both pathways.

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“…The DAST-induced ring expansion was studied in detail to perform the synthesis of piperidines from prolinol derivatives (Scheme 37). 52 Indeed, treatment of N-benzylprolinol 126 with DAST at 0 °C or lower temperature afforded a mixture of 2-(difluoromethyl)pyrrolidine 127 and 3-fluoropiperidine 128 in a 2:3 ratio. The reaction goes through the formation of an aziridinium ion, which gives the two products by fluoride ring-opening reaction.…”

Section: E Pfund T Lequeuxmentioning

confidence: 99%

Synthesis of Fluoropyrrolidines and (Fluoroalkyl)pyrrolidines

Pfund

Lequeux

2017

Synthesis

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Pyrrolidines and their derivatives are of great interest in medicinal chemistry and organic synthesis. Fluoropyrrolidines and (fluoroalkyl)pyrrolidines have been utilized in the preparation of medicinal drugs and also as organocatalysts. The synthesis of such compounds is achieved through the fluorination of pyrrolidine derivatives or by multistep synthesis from already containing fluoroalkyl precursors.1 Introduction1.1 General Interest of Fluorine-Containing Pyrrolidines1.2 Fluoroalkylpyrrolidines and the Gauche Effect2 Fluoropyrrolidines2.1 3-Fluoropyrrolidines2.2 3,3- and 3,4-Difluoropyrrolidines2.3 3,3,4-Trifluoropyrrolidines2.4 3,3,4,4-Tetrafluoropyrrolidines3 (Difluoromethyl)- and (Trifluoromethyl)pyrrolidines3.1 2-(Trifluoromethyl)pyrrolidines3.2 3- and 4-(Trifluoromethyl)pyrrolidines3.3 2-(Difluoromethyl)pyrrolidines3.4 3- and 4-(Difluoromethyl)pyrrolidines4 (Monofluoroalkyl)pyrrolidines4.1 2-(Monofluoromethyl)pyrrolidines4.2 2-(Monofluoroalkyl)pyrrolidines4.3 2-(Monofluoroalkenyl)pyrrolidines5 Conclusion

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Ring Expansion Induced by DAST: Synthesis of Substituted 3‐Fluoropiperidines from Prolinols and 3‐Fluoroazepanes from 2‐Hydroxymethylpiperidines

Cited by 48 publications

References 68 publications

Stereoselectively fluorinated N-heterocycles: a brief survey

Stereoselectively fluorinated N-heterocycles: a brief survey

Nucleophile‐Dependent Regio‐ and Stereoselective Ring Opening of 1‐Azoniabicyclo[3.1.0]hexane Tosylate

Synthesis of Fluoropyrrolidines and (Fluoroalkyl)pyrrolidines

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