Tetrahydrofuran → [4-(3-Hydroxypentan-3-yl)-2-methylphenyl]boronic acid

HRID 1443328Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 1443328
Br[C:2]1[CH:7]=[CH:6][C:5]([C:8]([OH:13])([CH2:11][CH3:12])[CH2:9][CH3:10])=[CH:4][C:3]=1[CH3:14].O1CCCC1.C([Li])CCC.[B:25](OC(C)C)([O:30]C(C)C)[O:26]C(C)C>CCCCCC>[CH2:9]([C:8]([C:5]1[CH:6]=[CH:7][C:2]([B:25]([OH:30])[OH:26])=[C:3]([CH3:14])[CH:4]=1)([OH:13])[CH2:11][CH3:12])[CH3:10]

Komponenten

6

Edukt 4

HCID 8028TetrahydrofuranHCID 21531Triisopropyl borateHCID 574330783-(4-Bromo-3-methyl-phenyl)-pentan-3-olHCID 178418339Butyllithium

Produkt 1

HCID 59167146[4-(3-Hydroxypentan-3-yl)-2-methylphenyl]boronic acidAusbeute 71 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 8058HexaneLösungsmittel

Reaktionsbedingungen

Temperatur
-70 °C

Versuchsvorschrift

In a three-necked flask, introduce under nitrogen 5 g of 3-(4-bromo-3-methylphenyl)pentan-3-ol (19.4 mmol) and 50 cm3 of tetrahydrofuran. Cool the mixture to −70° C. and add dropwise 23.3 cm3 (58 mmol) of a 2.5M solution of n-butyllithium in hexane, over 30 minutes. Leave the mixture for approximately 2 h with stirring at −70° C. and then add dropwise 13.5 cm3 of triisopropyl borate (58 mmol), over 20 minutes. Leave the mixture with stirring for 3 h, allowing the temperature to increase to −10° C. Hydrolyse the mixture with saturated NH4Cl solution and extract two times with ethyl acetate. Wash the combined organic phases with saturated sodium chloride solution and dry them over sodium sulfate. Evaporate the solvents under vacuum. This gives 5 g of a colorless oil, which is chromatographed on silica gel (heptane/ethyl acetate=9/1) to give 4-(1-ethyl-1-hydroxypropyl)-2-methylphenylboronic acid in the form of a highly viscous oil. (Yield=71%)

Aufarbeitung

  1. customLeave the mixture for approximately 2 h
  2. waitover 20 minutes
  3. customLeave the mixture
  4. stirringwith stirring for 3 h
  5. temperatureto increase to −10° C
  6. extractionHydrolyse the mixture with saturated NH4Cl solution and extract two times with ethyl acetate
  7. washWash the combined organic phases with saturated sodium chloride solution
  8. dry with materialdry them over sodium sulfate
  9. customEvaporate the solvents under vacuum
  10. customThis gives 5 g of a colorless oil, which is chromatographed on silica gel (heptane/ethyl acetate=9/1)

Quellen und Nachweise

ORD-Eintrag
ord-aea31dcd9fb0419facdcf05b3aeedaba
Quelldatensatz
uspto-grants-2010_02
Patentnummer
US07659421B2

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