Chemistry of novel compounds with multifunctional carbon structure. VI. Synthetic studies and 19F-nuclear magnetic resonance investigation of novel .ALPHA.,.ALPHA.-disubstituted fluoroacetates.

Takéuchi, Yoshio; Ogura, Hironobu; Ishii, Y.; Koizumi, Toru

doi:10.1248/cpb.38.2404

Cited by 16 publications

(4 citation statements)

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“…(+)-Ethyl 2-fluoro-2-phenylpropionate (9f): (54%), oil; 33% ee [α] 20 D +0.92 ( c 1.1, CHCl 3 ); 19 F NMR (CDCl 3 ) δ −152. Its spectral properties were in agreement with literature values …”

Section: Methodssupporting

confidence: 90%

“…Its spectral properties were in agreement with literature values. 53 Formation of (S)-(-)-2-Methyl-2-fluoro-1-tetralone (9a) Using Diethylaminosulfur Trifluoride (DAST). In a 25 mL oven-dried two-necked flask equipped with a rubber septum, an argon bubbler, and a magnetic stirring bar was placed 0.10 g (0.57 mmol) of (R)-(+)-2-hydroxy-2-methyl-1tetralone 33 (11, 95% ee) in CH2Cl2 (3 mL).…”

Section: Caution: Fluorine Is a Poisonous Corrosive Gas Which Is A Po...mentioning

confidence: 99%

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Asymmetric Fluorination of Enolates with Nonracemic N-Fluoro-2,10-Camphorsultams

et al. 1998

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The asymmetric “electrophilic” fluorination of tertiary enolates by nonracemic N-fluoro-2,10-camphorsultams 3 affords quaternary α-fluoro carbonyl compounds in modest yield and ee. The highest asymmetric induction was observed for the fluorination of the sodium enolate of 2-methyl-1-tetralone (8a) by (−)-N-fluoro-2,10-(3,3-dichlorocamphorsultam) (3b) to give (S)-(+)-2-fluoro-2-methyl-1-tetralone (9a) in 70% ee. The absolute configuration was established by X-ray crystallography of the corresponding diastereomeric β-hydroxy sulfoximine prepared from (±)-9a and the Johnson reagent. The asymmetric induction exhibited by 3 is opposite to that of the closely related enolate hydroxylation reagents nonracemic (camphorylsulfonyl)oxaziridines 4. The N-fluoro sultams 3 were prepared by fluorination (10% F2/N2) of the corresponding sultams 5.

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Section: Methodssupporting

confidence: 90%

Section: Caution: Fluorine Is a Poisonous Corrosive Gas Which Is A Po...mentioning

confidence: 99%

Asymmetric Fluorination of Enolates with Nonracemic N-Fluoro-2,10-Camphorsultams

et al. 1998

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“…Considering the above problems, we next focused on the structure that has no hydrogen on the chiral center, and we therefore prepared the diastereomeric esters and amides of compounds 63-66 (Fig. 3) [62].…”

Section: Evaluation Of Multifunctional Carbon Compounds As Cdamentioning

confidence: 99%

Synthesis, reactions, and applications of fluorine-containing multifunctional carbon compounds

Fujiwara¹,

Takéuchi²

2005

Journal of Fluorine Chemistry

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“…Herein, we report a novel and rapid method to prepare o -fluorophenols regioselectively with minimum transformation after fluorine incorporation using α-diazocyclohexenones as precursors. Diazo compounds are known to react with various electrophiles, including N -bromosuccinimide (NBS) and HF-pyridine, , PhSeX and PhIX 2 , , forming C–F bonds α to the carbonyl group. Therefore, by starting from α-diazocyclohexenone, we thought that halofluorination would afford an α-halo-α-fluoroketone that would undergo hydrohalide elimination followed by tautomerization to produce the fluorinated electron-rich arene o -fluorophenol (Scheme ).…”

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confidence: 99%

Preparation of o-Fluorophenols from Nonaromatic Precursors: Mechanistic Considerations for Adaptation to Fluorine-18 Radiolabeling

2015

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The preparation of fluorine-18 labeled o-fluorophenols at high specific activity is challenging and requires use of [18F]fluoride ion as the radioisotope source. As a novel, alternative approach, we found that treatment of α-diazocyclohexenones with Selectfluor™ and Et3N•3HF followed by HF elimination and tautomerization afforded ortho-fluorophenols regioselectively, rapidly. To adapt this chemistry to 18F radiolabeling, using bromine electrophiles in place of Selectfluor™ gave the o-fluorophenol via an α-bromo-α-fluoroketone intermediate in lower but still reasonable yields.

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Chemistry of novel compounds with multifunctional carbon structure. VI. Synthetic studies and 19F-nuclear magnetic resonance investigation of novel .ALPHA.,.ALPHA.-disubstituted fluoroacetates.

Cited by 16 publications

References 1 publication

Asymmetric Fluorination of Enolates with Nonracemic N-Fluoro-2,10-Camphorsultams

Asymmetric Fluorination of Enolates with Nonracemic N-Fluoro-2,10-Camphorsultams

Synthesis, reactions, and applications of fluorine-containing multifunctional carbon compounds

Preparation of o-Fluorophenols from Nonaromatic Precursors: Mechanistic Considerations for Adaptation to Fluorine-18 Radiolabeling

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