To a solution of the crude 4-t-butyldiphenylsiloxy-2,6-dimethoxybenzyl alcohol (4.01 g) obtained by the above-described procedure in anhydrous dimethylformamide (30 mL) were added imidazole (1.29 g, 18.98 mmol) and t-butylchlorodimethylsilane (1.79 g, 11.86 mmol). After stirring at 50° C. for 4 hours, water was added and the resulting mixture was extracted with ethyl acetate-hexane (1:2). The organic layer was washed with water, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to yield crude 4-(t-butyldimethylsiloxy)methyl-1-t-butyldiphenylsiloxy-3,5-dimethoxybenzene was obtained as a colorless amorphous powder (5.33 g).
