Potassium Iodide → 4,4-Dihexyl-4H-cyclopenta[1,2-b:5,4-b']bisthiophene

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Reaction Steps

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).

Provenance & Evidence