Triphenylphosphine → 2-{3-[(1S)-2-Methoxy-1-methylethoxy]-5-[4-(methylsulfonyl)phenoxy]phenyl}-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

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Reaction Conditions

Reaction Steps

3-[4-(Methylsulfonyl)phenoxy]-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenol (13.20 g, 33.8 mmol) synthesized in Example (1d) was dissolved in tetrahydrofuran (300 mL), and (R)-(−)-1-methoxy-2-propanol (3.70 mL, 37.8 mmol) and triphenylphosphine (9.78 g, 37.3 mmol) were added, and subsequently cooled to 0° C. Diethyl azodicarboxylate (40% toluene solution, 16.2 mL, 37.2 mmol) was added dropwise over 10 minutes under nitrogen atmosphere and stirring was carried out at 0° C. for 30 minutes, followed by raising the temperature naturally and stirring at room temperature overnight. Water (300 mL) and ethyl acetate (300 mL) were added, and the solution was separated. The organic layer was washed with saturated brine, and subsequently dried over sodium sulfate. The solvent was distilled off under reduced pressure, and the resulting residue was purified using silica gel column chromatography (elution solvent: ethyl acetate/hexane=20%-40%) to afford the desired compound (11.94 g, yield 76%) as a colorless oil.

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