Regioselective Synthesis of Difluorinated <i>C</i>-Furanosides Involving a Debenzylative Cycloetherification

Delbrouck, Julien A.; Bochatay, Valentin N.; Tikad, Abdellatif; Vincent, Stéphane

doi:10.1021/acs.orglett.9b01878

Cited by 6 publications

(13 citation statements)

References 41 publications

(60 reference statements)

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“…Moderate diastereoselectivity is also typical for reactions with other aldehydes carrying alkoxy functionality at the stereo centers. In most cases, the diastereomeric mixtures of the resulting α,α‐difluoro‐β‐hydroxy carboxylates could be separated [20b,35] . A remarkably high stereoselectivity was observed in the Reformatsky‐type reaction of benzyl‐protected mannolactone 22 .…”

Section: Asymmetric Difluoro‐reformatsky Reactionsmentioning

confidence: 99%

The Asymmetric Difluoro‐Reformatsky Reaction

Braun

2021

Eur J Org Chem

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The structural motif of α,α-difluoro-substituted carboxyl and carbonyl groups with hydroxy-or amino-substituents at the stereogenic carbon in β-position is found frequently in drugs and biologically active compounds. A straightforward method for obtaining those targets in high enantiomeric purity is given by asymmetric difluoro-Reformatsky and imino-difluoro-Reformatsky reactions that lead to α,α-difluorinated β-hydroxyand β-amino-carboxylates or β-lactams. Three concepts that open a route to this type of compounds are discussed here. Firstly, chiral substrates are able to induce stereoselectivity in the formation of the newly created stereogenic center. Secondly, covalently bound and removable chiral auxiliaries are used in asymmetric syntheses and, thirdly, chiral additives and ligands at the metal direct the addition of the zinc enolate, the Reformatsky reagent, to aldehydes or imines in an enantioselective manner. The review closes with a short discussion of more recently developed difluoro-aldol reactions that may be considered as alternatives to the Reformatsky procedure.

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Section: Asymmetric Difluoro‐reformatsky Reactionsmentioning

confidence: 99%

The Asymmetric Difluoro‐Reformatsky Reaction

Braun

2021

Eur J Org Chem

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“…More recently, the regioselective syntheses of difluorinated C-furanosides involving a debenzylative cycloetherification have been reported by Vincent and colleagues. [38] Our group has recently contributed with the description of a visible-light-photocatalyzed fluoroalkylation of 2-acetoxyglycals leading to the synthesis of a-1-fluoroalkyl-C-glycosyl derivatives. [39] The resulting a-1-fluoroalkyl-C-glycosyl compounds bear CF 3 , C 4 F 9 , and C 6 F 13 substituents on the anomeric carbon.…”

Section: Fluoroalkylation Of Carbohydrates and Derivatives: Endoglycals As Substratesmentioning

confidence: 99%

“…More recently, the regioselective syntheses of difluorinated C‐furanosides involving a debenzylative cycloetherification have been reported by Vincent and colleagues [38] …”

Section: Fluoroalkylation Of Carbohydrates and Derivatives: Endoglycals As Substratesmentioning

confidence: 99%

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Approaches to the Synthesis of Perfluoroalkyl‐Modified Carbohydrates and Derivatives: Thiosugars, Iminosugars, and Tetrahydro(thio)pyrans

Uhrig

Flores

Postigo

2021

Chemistry A European J

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Fluoroalkyl-substituted carbohydrates play relevant roles in diverse areas such as supramolecular chemistry, glycoconjugation, liquid crystals, and surfactants, with direct applications as wetting, antifreeze, and coating agents. In light of these promising applications, new methodologies for the late-stage incorporation of fluoroalkyl R F groups into carbohydrates and derivatives are herein presented as they are relevant to the synthetic carbohydrate community. Previously reviewed protocols for the installation of R F groups onto carbohydrates and derivatives will be succinctly summarized in the light of the new achievements. Fluoroalkylsubstituted iminosugars, on the other hand, are also interesting glycomimetic derivatives with prominent roles as glycosidases and glycosyltransferases inhibitors, as has recently been demonstrated. Also, they positively contribute to the study of sugar-protein interactions and enzyme mechanisms. New advances in the syntheses of fluoroalkyl-substituted iminosugars will also be presented here.

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“…The protected, such as a benzyl ether, oxygen function can also act as a nucleophile and attack the sp 3 -carbon atom connected to the effective leaving group in the debenzylative cycloetherification (DBCE) process. 11 − 15 This methodology was successfully used for the preparation of C -ethynyl 13 and C -vinyl 14 furanosides as shown in Scheme 1 a. During the synthesis of higher carbon sugars, we observed a similar rearrangement in which the protected oxygen nucleophile attacked the allylic analog in the S N 2′ mode, which afforded the corresponding tetrahydrofuran derivative ( Scheme 1 b).…”

Section: Introductionmentioning

confidence: 99%

Stereocontrolled Debenzylative Cycloetherification Reaction as a Route to Enantiopure C-Furanosides with Amino Substituents in the Side Chain

et al. 2020

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A highly efficient methodology of the preparation of synthetically important tetrahydrofuran derivatives with an amino substituent in the side chain is reported. This process is based on the stereocontrolled debenzylative cycloetherification (DBCE) reaction applied for chirons from the d - gluco - and d - manno -series and provides derivatives with new stereogenic centers. The influence of the electron-withdrawing group (EWG), present in the acyclic substrates with the mesyl leaving group, on the reactivity in the DBCE reaction was investigated both “in the flask” and by density functional theory (DFT) calculations. It was demonstrated that tetrahydrofuran derivatives with the benzoxime group (EWG = CHNOBn) are very good candidates for the subsequent highly stereoselective Grignard reaction.

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Regioselective Synthesis of Difluorinated C-Furanosides Involving a Debenzylative Cycloetherification

Cited by 6 publications

References 41 publications

The Asymmetric Difluoro‐Reformatsky Reaction

The Asymmetric Difluoro‐Reformatsky Reaction

Approaches to the Synthesis of Perfluoroalkyl‐Modified Carbohydrates and Derivatives: Thiosugars, Iminosugars, and Tetrahydro(thio)pyrans

Stereocontrolled Debenzylative Cycloetherification Reaction as a Route to Enantiopure C-Furanosides with Amino Substituents in the Side Chain

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