Chlorotrimethylsilane → (7-Bromo-9,9-dioctyl-9H-fluoren-2-yl)(trimethyl)silane

Participants

Reaction Steps

n-Butyllithium in hexane (6.0 mL, 1.6 M, 9.6 mmol) was added to a solution of 2,7-dibromo-9,9-di-n-octylfluorene (7) (5.00 g, 9.13 mmol) in dry THF (50 mL) in a schlenk flask at −78° C. and the mixture was stirred for 20 minutes. Then chlorotrimethylsilane (1.5 mL, 1.29 g, 1.3 equiv) was added and the reaction was allowed to slowly warm to room temperature. The mixture was stirred overnight and the reaction was quenched with saturated brine. The product was extracted into diethyl ether, and the extract was washed with brine and dried over MgSO4. The crude product was chromatographed on silica using hexane as eluent to give 2-bromo-7-trimethylsilyl-9,9-di-n-octylfluorene as a colourless oil, (3.50 g, 71%). n-Butyllithium in hexane (4.4 mL, 1.6 M, mmol) was added to a solution of 2-bromo-7-trimethylsilyl-9,9-di-n-octylfluorene (3.47 g, 6.41 mmol) in dry THF (75 mL) in a schlenk flask at −78° C., and the mixture was stirred for 20 minutes. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.44 mL, 1.31 g, 7.04 mmol) was added and the reaction was stirred for 24 h after warming to room temperature. The reaction was then quenched with brine, and the product was extracted into diethyl ether. The extract was washed with brine and dried over MgSO4. The crude product was chromatographed on silica using 0–3% ethylacetate in hexane as eluent, to give 8 as a colourless solid (2.67 g, 71%). 1H NMR (CD2Cl2): δ 7.73 (m, 4H) 7.51 (m, 2H) 1.99 (t, 4H, J=8.2 Hz) 1.36–0.54 (m, 42H) 0.31 (s, 9H)ppm. 13C NMR: δ 151.60, 151.34, 149.76, 145.29, 142.69, 141.07, 134.71, 133.01, 130.08, 129.03, 120.50, 120.25, 84.93, 56.22, 41.26, 33.01, 32.84, 31.11, 30.37, 25.98, 24.95, 23.85, 15.08, 0.01. FDMS m/z 588.90.

Provenance & Evidence