1151564-17-8

77-78-1

1151564-03-2

GENERAL STEPS: To a stirred solution of 2-chloro-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-phenol (830 g, 3.26 mol) in anhydrous DMF (4.15 L) was added potassium carbonate (1126.4 g, 8.15 mol) under inert atmosphere. Dimethyl sulfate (402 mL, 4.24 mol) was slowly added dropwise to control the exothermic nature of the reaction (the dropwise addition time was controlled to be within 30 minutes, and the reaction temperature was increased from 28°C to 55°C). After the dropwise addition was completed, stirring of the reaction mixture was continued for 10 minutes. The reaction mixture was slowly poured into a stirred aqueous 2 N hydrochloric acid solution (5.98 L) to control gas release. The resulting precipitate was stirred for 2 h, filtered and washed with water (1 L). The solid was dried in a vacuum oven with a desiccant for 4 days to give 2-(2-chloro-3-methoxyphenyl)-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (7a) as a white powder (746.7 g, 2.78 mol, 85% yield).