2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → 2-(4-Chloro-2-fluoro-3-methoxyphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 1-bromo-4-chloro-2-fluoro-3-methoxybenzene (3 g, 12.53 mmol) in tetrahydrofuran (20 mL) cooled to −10° C. was added isopropylmagnesium bromide (5.18 mL, 15.03 mmol) dropwise and the reaction mixture was stirred at −10° C. for 1 h. The reaction mixture was then warmed to 0° C. and stirred for 1 h. The reaction was then cooled to −10° C. and 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.56 mL, 12.53 mmol) was slowly added dropwise. The reaction mixture was allowed to warm to room temperature and stirred for 16 h. The reaction mixture was quenched with 5% aqueous sodium hydroxide and extracted with ethyl acetate (2×25 mL). The combined organic layers were washed with brine solution, dried over sodium sulfate, filtered and concentrated under reduced pressure to afford 2-(4-chloro-2-fluoro-3-methoxyphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (2.3 g, 8.03 mmol, 64% crude yield) as a brown oil. The material was carried forward without further purification. 1H NMR (400 MHz, CDCl3) δ ppm 7.35 (m, 1H), 7.15 (m, 1H), 3.95 (s, 3H), 1.33 (s, 6H), 1.23 (s, 6H).

Provenance & Evidence