Benzo[1,2-b:4,5-b'']dithiophene (BDT) is one of the widely used building blocks to produce polymer structures for highly efficient organic solar cells, in a blend with fullerene or non-fullerene acceptors.

1160823-77-7

1066-45-1

1160823-78-8

General procedure for the synthesis of 1,1'-[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-B:4,5-B']dithiophene-2,6-diyl]bis[1,1,1-trimethylstannane] from 4,8-bis[(2-ethylhexyl)oxy]benz[1,2-B:4,5-B']dithiophene-2,6-diyl]bis[1,1,1-trimethylstannane]: 4,8-bis[(2-ethylhexyl)oxy]benz[1,2-B:4,5-B']dithiophene (628 mg, 1.4 mm, 1.4 mm, 2.4 mm, 2.4 mm, 2.4 mm, 2.4 mm, 2.4 mm, 2.4 mm, 2.4 mm, 2.6 mm, 3.2 mm, 3.2 mm, 4.8-bis[(2-ethylhexyl)oxy]benz[1,2-B:4,5-B']dithiophene (628 mg, 1.4 mm), 3.4 mm, 4.8-bis[(2-ethyl hexyl)oxy]benzo[1,2-B:4,5-B']dithiophene (628 mg, 1.4 mmol) was added to a 50 mL flask, dissolved in 20 mL of THF, and cooled to -78°C. The mixture was then purified to -78°C by a slow dropwise reaction. At -78 °C, 3.5 mL of THF solution of n-butyllithium (molar amount of n-butyllithium was 3.5 mmol) was slowly added dropwise and the reaction was stirred for 0.5 hours. Subsequently, the reaction mixture was warmed to room temperature and then cooled to -78 °C. 4.2 mL of hexane solution of trimethyltin chloride (molar amount of trimethyltin chloride is 4.2 mmol) was quickly added, and then the reaction mixture was warmed to room temperature and reacted for 12 hours. After completion of the reaction, a large amount of water was added, extracted with hexane and the organic phase was dried with anhydrous Na2SO4. After removal of the solvent, recrystallization by isopropanol gave 867 mg of colorless needle-like crystals in 80.2% yield. The resulting product was 2,6-bis(trimethylstannyl)-4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-B:4,5-B']dithiophene.