[F:1][CH:2]([F:14])[O:3][C:4]1[CH:9]=[CH:8][C:7]([CH:10]=[CH:11][O:12]C)=[CH:6][CH:5]=1.Cl>CC(C)=O>[F:1][CH:2]([F:14])[O:3][C:4]1[CH:5]=[CH:6][C:7]([CH2:10][CH:11]=[O:12])=[CH:8][CH:9]=1To a solution of 1-difluoromethoxy-4-((E,Z)-2-methoxyvinyl)-benzene (E/Z ratio ˜3:2,) (1.58 g, 7.9 mmol, from step (i) above ) in acetone (20 mL) was added 3 M HCl (3.7 mL, 11.1 mmol) and the solution was stirred at 45° C. for 4 h. After concentration under reduced pressure, water (25 mL) was added to the residue and the aqueous phase was extracted with diethylether (2×50 mL). The combined organic phase was washed with saturated aqueous NaHCO3 (50 mL) and brine (50 mL), dried over Na2SO4, and concentrated in vacuo to give 1.32 g of crude product as a yellow oil with a purity of ca. 80%. The crude product was used directly in the subsequent reduction step without further purification.
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