Chlorotrimethylsilane → (3-Fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-phenyl)trimethylsilane

Participants

Reaction Conditions

Reaction Steps

A 2.5 M solution of n-butyllithium (3.5 mL, 8.5 mmol, 1.1 equiv) was added to a stirred solution of 1,4-dibromo-2-fluorobenzene (2.0 g, 7.9 mmol, 1.0 equiv) in tetrahydrofuran (26 mL) at −78° C. The resulting bright yellow solution was stirred at −78° C. for 15 minutes. 2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.8 mL, 8.7 mmol, 1.1 equiv) was added and the resulting pale yellow solution was stirred at −78° C. for 30 m. A 2.5 M solution of n-butyllithium (3.5 mL, 8.5 mmol, 1.1 equiv) was added and the resulting yellow/brown solution was stirred at −78° C. for 15 m. Chlorotrimethylsilane (2.2 mL, 17 mmol, 2.2 equiv) was added and the resulting pale yellow solution was allowed to slowly warm to 23° C., by allowing the dry ice/acetone bath to melt, and stirred for 18 h. The reaction mixture was diluted with water (150 mL) and extracted with dichloromethane (2×100 mL). The combined organic layers were dried (magnesium sulfate), gravity filtered, and concentrated by rotary evaporation to afford the title compound as a pale yellow powder (2.3 g, 99%): IR (thin film) 3058 (w), 2981 (s), 2932 (m), 1615 (m) cm−1; 1H NMR (400 MHz, CDCl3) δ 7.72 (dd, J=7.5, 6 Hz, 1H), 7.26 (m, 1H), 7.16 (d, J=7.5 Hz, 1H), 1.34 (s, 12H), 0.23 (s, 9H).

Provenance & Evidence