Hydrochloric Acid → 2-(2-Chloro-3-methoxyphenyl)-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane

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Reaction 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 dry DMF (4.15 L) was added potassium carbonate (1126.4 g, 8.15 mol) under an inert atmosphere. Me2SO4 (402 mL, 4.24 mol) was added slowly to control the resulting exotherm (addition over 30 minutes gave a temperature rise from 28° C. to 55° C.) and after complete addition the reaction was stirred for 10 minutes. The reaction mixture was added to stirring HCl (5.98 L, 2 N, aq.) very slowly to control effervescence and the resulting precipitate stirred for 2 hours. The solids were filtered and washed with water (1 L) and dried in a vacuum oven over drying agent for 4 days to give 2-(2-chloro-3-methoxy-phenyl)-4,4,5,5-tetramethyl-[1,3,2]dioxaborolane 7a as a white powder (746.7 g, 2.78 mol, 85%).

Provenance & Evidence