Reaction #1884948

Reaction equation

potassium iodide

4H-Cyclopenta[2,1-b:3,4-b′]dithiophene

hexyl bromide

→

4,4-Dihexyl-cyclopenta[2,1-b:3,4-b′]dithiophene

Solvents

dimethyl sulfoxide

Conditions

Workup

1. 1
   OtherThe mixture was purged with argon for 10 minutes
2. 2
   workup.ADDITIONfollowed by the slow addition of solid potassium hydroxide (2 g)
3. 3
   workup.ADDITIONThe mixture was then poured into de-ionized water (150 mL)
4. 4
   Extractionthe organic phase extracted with diethyl ether (4×100 mL)
5. 5
   OtherThe organic phases were collected
6. 6
   Washwashed with brine (100 mL)
7. 7
   DryingThe organic phase was dried over magnesium sulphate
8. 8
   Filtrationfiltered
9. 9
   Concentrationconcentrated
10. 10
    Otherto give the crude product as yellow oil
11. 11
    OtherPurification via flash chromatography with hexanes (monitored at 254 nm, collected at 320 nm)
12. 12
    Otherdrying under high vacuum for 48 hours
13. 13
    Othergave pure product as colorless oil

Procedure

To a solution of 4H-Cyclopenta[2,1-b:3,4-b′]dithiophene (CDT) (1.63 g, 9.14 mmol) in dimethyl sulfoxide (50 mL) was added hexyl bromide (3.1 g, 18.9 mmol) and a catalytic amount of potassium iodide (50 mg). The mixture was purged with argon for 10 minutes followed by the slow addition of solid potassium hydroxide (2 g). The now dark green mixture was stirred in the dark at room temperature for 72 hours. The mixture was then poured into de-ionized water (150 mL) and the organic phase extracted with diethyl ether (4×100 mL). The organic phases were collected and washed with brine (100 mL) and a saturated ammonium chloride solution (100 mL). The organic phase was dried over magnesium sulphate, filtered, and concentrated to give the crude product as yellow oil. Purification via flash chromatography with hexanes (monitored at 254 nm, collected at 320 nm) and drying under high vacuum for 48 hours gave pure product as colorless oil. Yield 2.8 g (88%). 1H NMR (500 MHz, CDCl3): δ=7.15 (d, 2H, 3JH-H=5 Hz), 6.94 (d, 2H, 3JH-H=5 Hz), 1.84 (m, 4H, C—CH2), 1.19 (m, 12H, alkyl-CH2), 0.95 (m, 4H, alkyl-CH2), 0.82 (m, 6H, alkyl-CH3).

Source