Rearrangement reactions in the fluorination of d-glucopyranoside at the C-4 position by DAST

Lin, Tzung-Sheng; Tsai, Wei-Tse; Liang, Pi‐Hui

doi:10.1016/j.tet.2016.06.075

Cited by 7 publications

(10 citation statements)

References 20 publications

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“…The synthetic methods of saponins have been well reviewed, providing complete information on the organic synthesis to perform SAR optimization [6,7]. Based on the research experiences on carbohydrate [8,9] and medicinal [10][11][12][13][14][15][16][17][18][19][20][21][22] chemistry in our lab, we summarize the biological effects and preliminary SAR results of synthetic saponins over the last five years to serve as a bridge between chemistry and biology, providing an insight for further structure optimization and mechanism studies, finally facilitating the development of saponin-based bioactive compounds.…”

Section: Introductionmentioning

confidence: 99%

Biological and Pharmacological Effects of Synthetic Saponins

Juang

Liang

2020

Molecules

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Saponins are amphiphilic molecules consisting of carbohydrate and either triterpenoid or steroid aglycone moieties and are noted for their multiple biological activities—Fungicidal, antimicrobial, antiviral, anti-inflammatory, anticancer, antioxidant and immunomodulatory effects have all been observed. Saponins from natural sources have long been used in herbal and traditional medicines; however, the isolation of complexed saponins from nature is difficult and laborious, due to the scarce amount and structure heterogeneity. Chemical synthesis is considered a powerful tool to expand the structural diversity of saponin, leading to the discovery of promising compounds. This review focuses on recent developments in the structure optimization and biological evaluation of synthetic triterpenoid and steroid saponin derivatives. By summarizing the structure–activity relationship (SAR) results, we hope to provide the direction for future development of saponin-based bioactive compounds.

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Section: Introductionmentioning

confidence: 99%

Biological and Pharmacological Effects of Synthetic Saponins

Juang

Liang

2020

Molecules

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“…During the synthesis of 4-deoxy-4-fluoro-KRN-7000 163 (fluorinated derivative of α-galactosyl ceramide) (Figure 10), the potent ligand for invariant natural killer T cells, the stereochemistry of the hydroxyl group at C4 was of importance (Scheme 37). [63] Treatment of 164 with diethylaminosulfur trifluoride gave as a major product 5-deoxy-5-fluoro-β-l-altrofuranoside 168. Although the Sn2 mechanism with inversion of configuration at the C4 position was expected, a compound 167 with retained configuration as the minor product was obtained (Scheme 37).…”

Section: Rearrangement Reactions 41 Neighboring Group Participation In the Synthesis Of Sugars Derivativesmentioning

confidence: 99%

“…It was formed according to the mechanism shown in the Scheme 38. [63] Recently, Hornik et al developed a synthetic pathway for the preparation of 3-and 4-deoxofluorinated analogues of dglucosamine and d-galactosamine. [64] The compounds obtained in these studies can be used as metabolic inhibitors of complex Scheme 32.…”

Section: Rearrangement Reactions 41 Neighboring Group Participation In the Synthesis Of Sugars Derivativesmentioning

confidence: 99%

Diethylaminosulfur Trifluoride (DAST) Mediated Transformations Leading to Valuable Building Blocks and Bioactive Compounds

Kaźmierczak

Bilska-Markowska

2021

Eur J Org Chem

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Nucleophilic fluorination is one of the fundamental reactions in organic chemistry, as well as a convenient tool for the synthesis of fluorinated building blocks with a potential biological activity. In this minireview, diethylaminosulfur trifluoride (DAST) mediated reactions leading to valuable building blocks and bioactive compounds will be discussed. We focused on results that have been published since 2010. Transformation of βamino alcohols, heterocyclic frameworks synthesis, as well as rearrangement reactions have been described in detail.

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“…To account for the retention of configuration (minor product) in the fluorination of compound 13, we proposed the involvement of an oxiranium-like intermediate A (Figure 3b). Interestingly, oxiranium ions in carbohydrate chemistry have been proposed as intermediates in the course of various reactions [20,29,35,36]. An equatorial fluorine atom at C2 (antiperiplanar to the C1-O5 bond) reduces the endocyclic oxygen polarizability, but also destabilizes a possible carbocation at C4 (the C2-F2 bond is antiperiplanar to the C3-C4 bond) [37].…”

Section: Entrymentioning

confidence: 99%

Fluorine effect in nucleophilic fluorination at C4 of 1,6-anhydro-2,3-dideoxy-2,3-difluoro-β-D-hexopyranose

Lainé

Denavit

Lessard

et al. 2020

Beilstein J. Org. Chem.

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In this work, we have developed a simple synthetic approach using Et3N·3HF as an alternative to the DAST reagent. We controlled the stereochemistry of the nucleophilic fluorination at C4 of 1,6-anhydro-2,3-dideoxy-2,3-difluoro-4-O-triflate-β-ᴅ-talopyranose using Et3N·3HF or in situ generated Et3N·1HF. The influence of the fluorine atom at C2 on reactivity at C4 could contribute to a new fluorine effect in nucleophilic substitution. Finally, with the continuous objective of synthesizing novel multi-vicinal fluorosugars, we prepared one difluorinated and one trifluorinated alditol analogue.

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Rearrangement reactions in the fluorination of d-glucopyranoside at the C-4 position by DAST

Cited by 7 publications

References 20 publications

Biological and Pharmacological Effects of Synthetic Saponins

Biological and Pharmacological Effects of Synthetic Saponins

Diethylaminosulfur Trifluoride (DAST) Mediated Transformations Leading to Valuable Building Blocks and Bioactive Compounds

Fluorine effect in nucleophilic fluorination at C4 of 1,6-anhydro-2,3-dideoxy-2,3-difluoro-β-D-hexopyranose

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