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Search for "pyrrolidines" in Full Text gives 84 result(s) in Beilstein Journal of Organic Chemistry.

Stereoselective synthesis of four possible isomers of streptopyrrolidine

  • Debendra K. Mohapatra,
  • Barla Thirupathi,
  • Pragna P. Das and
  • Jhillu S. Yadav

Beilstein J. Org. Chem. 2011, 7, 34–39, doi:10.3762/bjoc.7.6

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  • Streptomyces sp. found in deep sea sediments [12]. The system is present in many biologically active compounds [13][14][15][16][17][18][19][20][21] and it could act as a versatile intermediate for the synthesis of a wide range of γ-amino acids as well as pyrrolidines [22][23]. The interesting chemical
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Published 10 Jan 2011

Prins fluorination cyclisations: Preparation of 4-fluoro-pyran and -piperidine heterocycles

  • Guillaume G. Launay,
  • Alexandra M. Z. Slawin and
  • David O'Hagan

Beilstein J. Org. Chem. 2010, 6, No. 41, doi:10.3762/bjoc.6.41

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  • methodology was extended to the aza-Prins reaction using N-tosyl-homoallylic amines to generate the corresponding 4-fluoropyrrolidines. In general, these reactions leading to both the 4-fluorotetrahydropyrans and 4-fluoro-pyrrolidines occur with good to high conversions, however the diastereoselectivities are
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Published 26 Apr 2010

Diastereoselective functionalisation of benzo-annulated bicyclic sultams: Application for the synthesis of cis-2,4-diarylpyrrolidines

  • Susan Kelleher,
  • Pierre-Yves Quesne and
  • Paul Evans

Beilstein J. Org. Chem. 2009, 5, No. 69, doi:10.3762/bjoc.5.69

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  • place to afford cis-2,4-diaryl-substituted pyrrolidines 35–37. Keywords: cyclic sulfonamides; diastereoselective alkene functionalisation; double reduction; Pd-mediated cross coupling; Introduction Substituted pyrrolidine ring systems represent a common structural motif in a range of biologically
  • active compounds, including pharmaceutical agents and natural products. In relation to these general targets, we have recently developed a method that enables the construction of aryl-substituted pyrrolidines, featuring the double reduction of cyclic aromatic sulfonamides [1][2][3][4]. As illustrated in
  • preparation of 2,4-diaryl-substituted pyrrolidines from more readily available, albeit racemic, substrates. Results and Discussion Bicyclic aromatic cyclic sulfonamides 5a and 5b were formed according to the 3-step sequence previously described [1][2][3][10]. Originally, inclusion of triphenylphosphine was
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Published 25 Nov 2009

Radical cascades using enantioenriched 7-azabenzonorbornenes and their applications in synthesis

  • David M. Hodgson and
  • Leonard H. Winning

Beilstein J. Org. Chem. 2008, 4, No. 38, doi:10.3762/bjoc.4.38

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  • -azabenzonorbornadienes. Oxidation (using RuO4) and Birch reduction of the 2-aza-5,6-benzonorbornenes provide access to substituted pyrrolidines and tetrahydroindenes, respectively. Keywords: asymmetric synthesis; deoxygenation; radicals; rearrangements; tandem reactions; Introduction Carbon-centred radicals have been
  • –oxidation with (−)-Ipc2BH to be determined by chemical correlation. Pyrrolidine 35 was independently prepared from (1R)-(−)-2-azabicyclo[2.2.1]hept-5-en-3-one (Vince’s lactam [36], 37) via reduction with LiAlH4, Boc-protection and oxidative cleavage [37] (Scheme 9). The pyrrolidines prepared from rearranged
  • the intermediate radical undergoes rearrangement prior to electrophile trapping, thereby providing a new route to substituted 2-aza-5,6-benzonorbornenes. These adducts have been shown to lead on to pharmaceutically significant [40] (aminomethyl)indenes, and to substituted pyrrolidines and
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Published 24 Oct 2008

C2-symmetric bisamidines: Chiral Brønsted bases catalysing the Diels- Alder reaction of anthrones

  • Deniz Akalay,
  • Gerd Dürner,
  • Jan W. Bats and
  • Michael W. Göbel

Beilstein J. Org. Chem. 2008, 4, No. 28, doi:10.3762/bjoc.4.28

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  • exerted by chiral Brønsted bases. Moderate to excellent stereoselectivities of products 3 have been reported using pyrrolidines 4 [1][2], cyclic guanidine 5 [3], or cinchona alkaloids 6 [4] as catalysts. Recently, we could promote this type of cycloaddition by metal-free bisoxazolines 7 in up to 70% ee
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Published 07 Aug 2008

Knorr- Rabe partial reduction of pyrroles: Application to the synthesis of indolizidine alkaloids

  • Brendon S. Gourlay,
  • John H. Ryan and
  • Jason A. Smith

Beilstein J. Org. Chem. 2008, 4, No. 3, doi:10.1186/1860-5397-4-3

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  • confirmed by comparison of the spectral data with that reported by Huxtable who prepared 9 as an intermediate in the synthesis of lentiginosine [12]. For the partial reduction of electron rich pyrroles reported previously, over reduction to give pyrrolidines is a problematic side-reaction. For example
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Published 15 Jan 2008

Desymmetrization of 7-azabicycloalkenes by tandem olefin metathesis for the preparation of natural product scaffolds

  • Wolfgang Maison,
  • Marina Büchert and
  • Nina Deppermann

Beilstein J. Org. Chem. 2007, 3, No. 48, doi:10.1186/1860-5397-3-48

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  • -azabicycloalkenes by intra- and intermolecular tandem metathesis sequences with ruthenium based catalysts. Conclusion Desymmetrization of 7-azabicycloalkenes by olefin metathesis is an efficient process for the preparation of common natural product scaffolds such as pyrrolidines, indolizidines and isoindoles
  • azabicycloalkane scaffolds was first described by Grubbs[23] for the synthesis of peptide mimetics and later extended by several other groups. [24][25][26][27][28][29][30][31] Key intermediates in these approaches are often alkenyl substituted pyrrolidines, which are N-acylated with an unsaturated carboxylic acid
  • and submitted to a ring closing metathesis (RCM). As a part of a general synthetic concept using azabicycloalkenes as masked analogs of functionalized pyrrolidines or piperidines [32][33][34][35][36][37][38][39] we have previously applied the concept of intramolecular ring-opening/ring-closing
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Published 18 Dec 2007

The enantiospecific synthesis of (+)-monomorine I using a 5-endo- trig cyclisation strategy

  • Malcolm B. Berry,
  • Donald Craig,
  • Philip S. Jones and
  • Gareth J. Rowlands

Beilstein J. Org. Chem. 2007, 3, No. 39, doi:10.1186/1860-5397-3-39

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  • University, Private Bag 11 222, Palmerston North, New Zealand 10.1186/1860-5397-3-39 Abstract We have developed a general strategy for the synthesis of 2,5-syn disubstituted pyrrolidines that is based on the multi-faceted reactivity of the sulfone moiety and a 5-endo-trig cyclisation. This methodology was
  • , such as tetrahydrofurans and pyrrolidines, makes these motifs attractive targets for synthesis. Over the last decade we have developed a powerful general strategy for the preparation of such compounds based upon the multi-faceted reactivity of the sulfone group and the formally disfavoured 5-endo-trig
  • mode of cyclisation. [1][2][3][4][5][6] The methodology allows the conversion of epoxides (X = O) or aziridines (X = N-PG) (2) into the desired trisubstituted tetrahydrofurans or pyrrolidines (5) via a series of sulfone-mediated transformations (Scheme 1). Ring-opening 2 with the sulfone-stabilised
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Published 08 Nov 2007

An asymmetric synthesis of all stereoisomers of piclavines A1-4 using an iterative asymmetric dihydroxylation

  • Yukako Saito,
  • Naoki Okamoto and
  • Hiroki Takahata

Beilstein J. Org. Chem. 2007, 3, No. 37, doi:10.1186/1860-5397-3-37

Graphical Abstract
  • monocyclic compounds (pyrrolidines) to bicyclic derivatives (indolizidines) provides rigid conformation and causes close proximity (a change from 1,5- to 1,3-relationship) between the two asymmetric centers. With indolizidine (5R, 8aR)-18 in hand, we examined partial-reduction of their triple bonds. First
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Published 29 Oct 2007
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