Реакция #70957

Уравнение реакции

1,2-bis(2,5-dimethyl-3-thienyl)ethanedione

benzene

Potassium t-butoxide

benzene

→

25

Выход 25.0%

3,4-bis(2,5-dimethyl-3-thienyl)cyclohexadiene

Выход 25.0%

Условия реакции

Обработка

1. 1
   ТемператураThe resulting orange solution was heated
2. 2
   Температураto reflux
3. 3
   workup.STIRRINGThe reaction mixture was stirred
4. 4
   Температураat reflux for 20 min, at which point the heating mantle
5. 5
   Другоеwas removed
6. 6
   Температураto cool to room temperature
7. 7
   ДругоеThe reaction was quenched by the addition of water (50 mL)
8. 8
   Экстракцияextracted with Et2O (3×50 mL)
9. 9
   Промывкаwashed with brine
10. 10
    Сушкаdried over MgSO4
11. 11
    Фильтрацияfiltered
12. 12
    ДругоеThe solvent was removed under reduced pressure
13. 13
    Другоеthe residue was purified by column chromatography through silica (1:9 EtOAc:hexanes)

Методика

Potassium t-butoxide (163 mg, 1.45 mmol) was added to a suspension of 1,4-butanebis(triphenylphosphonium)dibromide (537 mg, 0.725 mmol) in benzene (50 mL). The reaction was stirred for 45 min at room temperature. The resulting orange solution was heated to reflux and treated drop-wise with a solution of 1,2-bis(2,5-dimethyl-3-thienyl)ethanedione 23 (202 mg, 0.72 mmol) in benzene (25 mL). The reaction mixture was stirred at reflux for 20 min, at which point the heating mantle was removed and the reaction was allowed to cool to room temperature. The reaction was quenched by the addition of water (50 mL) and extracted with Et2O (3×50 mL). The organic extracts were combined, washed with brine, dried over MgSO4 and filtered. The solvent was removed under reduced pressure and the residue was purified by column chromatography through silica (1:9 EtOAc:hexanes) to yield 55 mg (25%) of 25 as a white solid. Mp=55-57° C. 1H NMR (CDCl3): δ=6.13 (s, 2H), 5.88 (m, 2H), 2.26 (m, 10H), 2.14 (s, 6H); 13C NMR (CDCl3) δ=137.8, 134.4, 133.9, 131.6, 127.4, 126.7, 22.7, 15.1, 14.0. MS (EI): m/z=300 (M+).

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