6-bromo-2,2-dimethyl-4H-spiro[chromene-3,1'-cyclopropan]-4-one → 6-bromo-2,2-dimethyl-4-methylene-4H-spiro[chromene-3,1'-cyclopropane]

HRID 873735Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 873735
[CH2:1]([Li])CCC.[Br:6][C:7]1[CH:8]=[C:9]2[C:16](=[CH:17][CH:18]=1)[O:15][C:14]([CH3:20])([CH3:19])[C:11]1([CH2:13][CH2:12]1)[C:10]2=O>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.O1CCCC1>[Br:6][C:7]1[CH:8]=[C:9]2[C:16](=[CH:17][CH:18]=1)[O:15][C:14]([CH3:20])([CH3:19])[C:11]1([CH2:13][CH2:12]1)[C:10]2=[CH2:1]

Komponenten

5

Edukt 2

HCID 867242776-bromo-2,2-dimethyl-4H-spiro[chromene-3,1'-cyclopropan]-4-oneHCID 178418339Butyllithium

Produkt 1

HCID 867242836-bromo-2,2-dimethyl-4-methylene-4H-spiro[chromene-3,1'-cyclopropane]Ausbeute 95 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 74505Methyltriphenyliphosphonium bromideKatalysatorHCID 8028TetrahydrofuranLösungsmittel

Reaktionsbedingungen

Temperatur
0 °C

Versuchsvorschrift

To a suspension of methyl(triphenyl)phosphonium bromide (20.8 g, 58.2 mmol) in tetrahydrofuran (168 ml) was added n-butyllithium (2.69 M solution in hexane, 21.6 ml, 58.2 mmol) under dry ice-acetone bath cooling and argon atmosphere. The mixture was stirred for 1 hour at 0° C. To the mixture was added 6-bromo-2,2-dimethyl-4H-spiro[chromene-3,1′-cyclopropan]-4-one (8.18 g, 29 mmol). The mixture was stirred for 1 hour at 0° C. The reaction was quenched by adding water and extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous magnesium sulfate, and concentrated in vacuo. The residue was purified by silicagel column chromatography (hexane/ethyl acetate=20:1-10:1) to afford 6-bromo-2,2-dimethyl-4-methylene-4H-spiro[chromene-3,1′-cyclopropane] (7.69 g).

Aufarbeitung

  1. temperaturecooling
  2. stirringThe mixture was stirred for 1 hour at 0° C
  3. customThe reaction was quenched
  4. additionby adding water
  5. extractionextracted with ethyl acetate
  6. washThe organic layer was washed with brine
  7. dry with materialdried over anhydrous magnesium sulfate
  8. concentrationconcentrated in vacuo
  9. customThe residue was purified by silicagel column chromatography (hexane/ethyl acetate=20:1-10:1)

Quellen und Nachweise

ORD-Eintrag
ord-bad599bd1b8947e4a5346ebc245371a2
Quelldatensatz
uspto-grants-2015_03
Patentnummer
US08975415B2

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