Enantioselective and diastereoselective synthesis of fluorinated dipeptides by late electrophilic fluorination

Mohar, Barbara; Šterk, Damjan; Ferron, Laurent; Cahard, Dominique

doi:10.1016/j.tetlet.2005.05.074

Cited by 26 publications

(16 citation statements)

References 20 publications

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“…This structural element is well-known to rapidly eliminate fluoride, which is one of the main reasons why α-F-α-amino acid derivatives are very rare and sensitive motives. [28,29,30] However, given the fact that the presence of an electron-withdrawing N-substituent is supposed to increase the stability of the α-F-α-amino acid motive [29,30] we tested the α-fluorination of nucleophilic isoindolinones 1.…”

Section: Updates Ascwiley-vchdementioning

confidence: 99%

Enantioselective Bifunctional Ammonium Salt‐Catalyzed Syntheses of 3‐CF₃S‐, 3‐RS‐, and 3‐F‐Substituted Isoindolinones

et al. 2021

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We herein report the ammonium saltcatalyzed synthesis of chiral 3,3-disubstituted isoindolinones bearing a heteroatom functionality in the 3-position. A broad variety of differently substituted CF 3 Sand RS-derivatives were obtained with often high enantioselectivities when using Maruoka's bifunctional chiral ammonium salt catalyst. In addition, a first proof-of-concept for the racemic synthesis of the analogous F-containing products was obtained as well, giving access to one of the rare examples of a fairly stable α-F-α-amino acid derivative.

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Section: Updates Ascwiley-vchdementioning

confidence: 99%

Enantioselective Bifunctional Ammonium Salt‐Catalyzed Syntheses of 3‐CF₃S‐, 3‐RS‐, and 3‐F‐Substituted Isoindolinones

et al. 2021

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“…The opposite strategy in the electrophilic fluorination was reported on a-nitrogen monocarbonyl compounds with the aim to get a-fluoro-a-amino acid derivatives, but the phthalimide protection at the nitrogen atom could not be removed without dehydrofluorination. 7,38 Carbon-sulfur bond formation Togni and Jereb reported the enantioselective sulfenylation of 1,3-dicarbonyl compounds with phenylsulfenyl chloride catalyzed by a Ti(TADDOLato) complex (Scheme 22). The tert-butyl ester of 2-fluoro-3-oxobutanoic acid was used in the catalytic asymmetric sulfenylation reaction and the desired compound was formed with 89% ee in toluene with 5 mol% of chiral catalyst.…”

Section: Carbon-nitrogen Bond Formationmentioning

confidence: 99%

Fluorine & chirality: how to create a nonracemic stereogenic carbon–fluorine centre?

et al. 2010

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Enantiopure organofluorine compounds are at the forefront of innovation in the field of fluorine chemistry. The significant progress in modern fluoroorganic chemistry parallels the tremendous achievements in organocatalysis and organometallic catalysis that have permitted the asymmetric synthesis of chiral chemicals featuring a fluorinated stereogenic carbon centre. This tutorial review provides an overview of the current state of the art in asymmetric construction of stereogenic carbon-fluorine centres, not only by direct fluorination, but also by asymmetric reaction of fluorinated substrates.

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“…Asymmetric C-F bond formation continues to challenge chemists, inspiring the development of increasingly effective protocols for stereocontrolled fluorination. [ 1 - 11 ] Studies from our laboratory illustrated that allylsilanes undergo electrophilic fluorination to afford allylic fluorides with clean transposition of the double bond. Using chiral cyclic allylsilanes, these experiments have culminated in efficient methods for the asymmetric synthesis of monofluorinated cyclitols or vitamin D3 analogues.…”

Section: Resultsmentioning

confidence: 99%

Single and double stereoselective fluorination of (E)-allylsilanes

Sawicki¹,

Kwok²,

Tredwell³

et al. 2007

Beilstein J. Org. Chem.

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Acyclic allylic monofluorides were prepared by electrophilic fluorination of branched (E)-allylsilanes with Selectfluor. These reactions proceeded with efficient transfer of chirality from the silylated to the fluorinated stereocentre. Upon double fluorination, an unsymmetrical ethyl syn-2,5-difluoroalk-3-enoic ester was prepared, the silyl group acting as an anti stereodirecting group for the two C-F bond forming events.Page 1 of (page number not for citation purposes) FindingsAsymmetric C-F bond formation continues to challenge chemists, inspiring the development of increasingly effective protocols for stereocontrolled fluorination. [1][2][3][4][5][6][7][8][9][10][11] Studies from our laboratory illustrated that allylsilanes undergo electrophilic fluorination to afford allylic fluorides with clean transposition of the double bond. Using chiral cyclic allylsilanes, these experiments have culminated in efficient methods for the asymmetric synthesis of monofluorinated cyclitols or vitamin D3 analogues. [12][13][14][15] The key step of these syntheses is a highly efficient diastereoselective fluorodesilylation. We encountered more difficulties with the fluorination of acyclic allylsilanes A constructed by metathetic coupling of allyltrimethysilane with chiral olefinic partners (eq. 1, Scheme 1). Although high yielding, the electrophilic fluorination of these substrates suffered from a poor level of diastereocontrol, thereby limiting the synthetic value of these reactions. [16,17] The absence of a silylated stereogenic centre is likely to be responsible for the poor stereocontrol observed upon fluorination of these substrates. We envisaged that the fluorination of (E)-allylsilanes B, featuring a silylated stereogenic centre, might be a superior transformation to control the configuration of the emerging fluorine-bearing centre (eq. 2, Scheme 1). This working hypothesis is supported by the well-accepted model, which accounts for the observed transfer of chirality when reacting allylsilanes B with electrophiles other than fluorine. [18][19][20][21] Chiral allylsilanes B are known to act as useful carbon nucleophile equivalents in highly stereoselective condensation reactions with a large range of electrophiles leading to the construction of C-C, C-O, C-N or C-S bonds. [22][23][24][25][26][27] Herein, we report our investigation into the fluorination of (E)-allylsilanes of general structure B. A highly efficient and stereoselective synthesis of alkenes featuring bis-allylic stereocentres, one of them being fluorinated, emerged from this study. Significantly, alkenes flanked by two allylic fluorinated stereogenic centres are also accessible upon double electrophilic fluorination of (E)-allylsilanes substituted with an ester group.The synthesis of the allylsilanes (±)-1a-i featuring an ester or alcohol group was carried out according to the procedure reported by Panek and co-workers.[30] See Supporting Information File 1 for full experimental data. The fluorinations were carried out at room temperature in CH 3...

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Enantioselective and diastereoselective synthesis of fluorinated dipeptides by late electrophilic fluorination

Cited by 26 publications

References 20 publications

Enantioselective Bifunctional Ammonium Salt‐Catalyzed Syntheses of 3‐CF₃S‐, 3‐RS‐, and 3‐F‐Substituted Isoindolinones

Enantioselective Bifunctional Ammonium Salt‐Catalyzed Syntheses of 3‐CF₃S‐, 3‐RS‐, and 3‐F‐Substituted Isoindolinones

Fluorine & chirality: how to create a nonracemic stereogenic carbon–fluorine centre?

Single and double stereoselective fluorination of (E)-allylsilanes

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Enantioselective and diastereoselective synthesis of fluorinated dipeptides by late electrophilic fluorination

Cited by 26 publications

References 20 publications

Enantioselective Bifunctional Ammonium Salt‐Catalyzed Syntheses of 3‐CF3S‐, 3‐RS‐, and 3‐F‐Substituted Isoindolinones

Enantioselective Bifunctional Ammonium Salt‐Catalyzed Syntheses of 3‐CF3S‐, 3‐RS‐, and 3‐F‐Substituted Isoindolinones

Fluorine & chirality: how to create a nonracemic stereogenic carbon–fluorine centre?

Single and double stereoselective fluorination of (E)-allylsilanes

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Enantioselective Bifunctional Ammonium Salt‐Catalyzed Syntheses of 3‐CF₃S‐, 3‐RS‐, and 3‐F‐Substituted Isoindolinones

Enantioselective Bifunctional Ammonium Salt‐Catalyzed Syntheses of 3‐CF₃S‐, 3‐RS‐, and 3‐F‐Substituted Isoindolinones