To a solution of 2,7-dibromo-9,9-didecylfluorene (95.5 g, 0.158 mol) in terahydrofuran (THF, 375 mL), cooled In a dry-ice acetone bath, a 1.6 M solution of n-butyl lithium in hexanes (100 mL) was added over a period of 25 minutes. After stirring for 30 minutes a solution of dimethylforamide (DMF, 23 mL) in THF (25 ml) was added and the mixture was stirred for 1 hour in the cooling bath. After the mixture had been warmed to 0° C., hydrochloric acid (1:1, 50 mL) was added, diluted with toluene and the organic phase was separated, dried and concentrated. The residue that remained after rotary evaporation of the solvents was chromatographed over 600 g of silica gel. After elution with hexanes, the column was eluted with 1:3 toluene-hexane to obtain the aldehyde, 70.5 g, (81% yield), m.p. 45-47° C. A sample was recrystallized from a mixture of isopropanol and methanol, m.p. 49-49.5° C. IR (KBr; cm−1): 2922, 2853, 1696 (C═O), 1605, 1459. Anal. Calcd. for C34H49BrO: C, 73.76%; H, 8.92%; Br, 14.43%. Found: C, 73.75%; H, 8.86%; Br, 14.64%.
