3-Methoxycyclohex-2-en-1-one → Spiro[2.5]octan-5-one

HRID 905943

Reaktionsgleichung

Reaktionsgleichung von HRID 905943
CO[C:3]1[CH2:8][CH2:7][CH2:6][C:5](=[O:9])[CH:4]=1.[CH2:10]([Mg]Br)[CH3:11].O.C1(C)C=CC(S(O)(=O)=O)=CC=1>CCOCC.CC(C)[O-].CC(C)[O-].CC(C)[O-].CC(C)[O-].[Ti+4]>[CH2:10]1[C:3]2([CH2:8][CH2:7][CH2:6][C:5](=[O:9])[CH2:4]2)[CH2:11]1

Komponenten

6

Edukt 3

HCID 855973-Methoxycyclohex-2-en-1-oneHCID 521998p-Toluenesulfonic acid monohydrateHCID 178418443HCID 178418443, Verbindung

Produkt 1

HCID 12153480Spiro[2.5]octan-5-oneAusbeute 32,6 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 11026Titanium isopropoxideKatalysatorHCID 3283Diethyl EtherLösungsmittel

Versuchsvorschrift

3-Methoxy-cyclohex-2-enone (7.8 g, 61.83 mmol) was dissolved in Et2O (100 mL) and titanium tetraisopropoxide (20.1 mL, 68.01 mmol) was added. To the resulting brown solution ethylmagnesium bromide solution (3M, 60 mL, 180 mmol) was added dropwise over 70 minutes. A precipitate formed over the course of the addition. After 2 hours at RT the now dark brown/black reaction mixture was carefully quenched with saturated aqueous NH4Cl. A dark gray precipitate formed and was filtered off over Celite. The aqueous layer was extracted twice with Et2O. The combined organic layers were washed with brine, dried (Na2SO4), filtered, and evaporated. The residue was taken up in Et2O (100 mL) and p-toluenesulfonic acid monohydrate (0.588 g, 3.091 mmol) was added. The resulting brown solution was stirred at RT over the weekend before being evaporated. The remaining brown oil was purified by SiO2 chromatography (330 g SiO2, hexanes/EtOAc 0 to 7% EtOAc) to give 2.5 g of spiro[2.5]octan-5-one as a light yellow liquid (32% yield).

Aufarbeitung

  1. customA precipitate formed over the course of the addition
  2. customAfter 2 hours at RT the now dark brown/black reaction mixture was carefully quenched with saturated aqueous NH4Cl
  3. customA dark gray precipitate formed
  4. filtrationwas filtered off over Celite
  5. extractionThe aqueous layer was extracted twice with Et2O
  6. washThe combined organic layers were washed with brine
  7. dry with materialdried (Na2SO4)
  8. filtrationfiltered
  9. customevaporated
  10. custombefore being evaporated
  11. customThe remaining brown oil was purified by SiO2 chromatography (330 g SiO2, hexanes/EtOAc 0 to 7% EtOAc)

Quellen und Nachweise

ORD-Eintrag
ord-6f48c18dff9e41359c50eacc28125c8b
Quelldatensatz
uspto-grants-2011_09
Patentnummer
US08012974B2

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