Reaktion #811534

Reaktionsgleichung

3-(4-tert-Butyl-phenyl)-2,5-dimethyl-5,6-dihydro-cyclopenta[b]thiophen-4-one

lithium aluminum hydride

ammonium chloride

→

3-(4-tert-Butyl-phenyl)-2,5-dimethyl-6H-cyclopenta[b]thiophene

Lösungsmittel

diethyl ether

Reaktionsbedingungen

Aufarbeitung

1. 1
   FiltrationThe solids were filtered
2. 2
   Sonstigethe organics were collected with 30% dichloromethane/70% hexane
3. 3
   Waschenwashed with water
4. 4
   Trocknendried over magnesium sulfate
5. 5
   Filtrationfiltered
6. 6
   Sonstigesolvents removed in vacuo
7. 7
   workup.DISSOLUTIONThe partially dehydrated product (12.3 g of a brown oil), was dissolved in 50 ml toluene
8. 8
   workup.ADDITIONa catalytic amount of para-toluenesulfonic acid monohydride (0.25 g) was added
9. 9
   TemperaturThe flask contents were refluxed for 1 h
10. 10
    workup.STIRRINGstirred at room temperature overnight
11. 11
    WaschenThe organic fraction was washed with water
12. 12
    Trocknendried over magnesium sulfate
13. 13
    Filtrationfiltered
14. 14
    Sonstigesolvents removed in vacuo

Vorschrift

To a solution containing 12.9 g (43 mmol) 3-(4-tert-Butyl-phenyl)-2,5-dimethyl-5,6-dihydro-cyclopenta[b]thiophen-4-one dissolved in 100 ml diethyl ether was added 22 mmol lithium aluminum hydride (1M in diethyl ether, 22 ml added) at room temperature. The reaction mixture was stirred for 2.5 h, then a saturated solution of ammonium chloride was slowly added (3 ml). The solids were filtered and the organics were collected with 30% dichloromethane/70% hexane, washed with water, dried over magnesium sulfate, filtered, then solvents removed in vacuo. The partially dehydrated product (12.3 g of a brown oil), was dissolved in 50 ml toluene and a catalytic amount of para-toluenesulfonic acid monohydride (0.25 g) was added, The flask contents were refluxed for 1 h, then stirred at room temperature overnight. The organic fraction was washed with water, dried over magnesium sulfate, filtered, then solvents removed in vacuo. Yield: 10.1 g (77.4%) dark brown oil. Olefin: (2 isomers); 1H NMR (CD2Cl2): δ 7.1–7.7 (m, 4H), 6.4–6.5 (2s, 1H), 3.18, 3.3 (2s, 2H), 2.4–2.6 (m, 3H), 2.18 (m, 3H), 1.4 (s, 12H).

Quelle