In a flame-dried, 1 L rbf, 3-bromo-5,5″-di-t-butyl-2,2′:5′,2″-terthiophene (112, 4 g, 9.10 mmol) was dissolved in anhydrous diethyl ether (400 mL) and cooled to −48° C. (dry ice/acetone). n-BuLi (2.5 M in hexanes, 1.5 mL, 3.82 mmol) was added dropwise over a period of 5 minutes. The resulting yellow solution was allowed to stir for 20 minutes, then octafluorocyclopentene (0.24 mL, 1.82 mmol) was added in one portion. The reaction mixture warmed to −45° C. The reaction mixture was allowed to mix and slowly warm to 5° C., and then was poured into water (300 mL) and mixed well, then acidified with 10% HCl (100 mL). The aqueous phase was separated and extracted with EtOAc (2×100 mL). The combined organics were washed with water (500 mL), dried over MgSO4, filtered and solvent removed by rotary evaporation. The resulting dark orange oil was redissolved in chloroform and dry-loaded onto silica gel. Flash chromatography (hexanes) afforded a yellow oil, which was sonicated in methanol, filtered and air dried to afford 113 as a bright yellow, powdery solid (3.62 g, 72%).
