A stirred solution of propargyl alcohol (0.1 g, 1.78 mmol) in dry THF at −78° C. under nitrogen was treated dropwise with 1.9 M n-BuLi (1.88 mL, 3.57 mmol) over 10 min, stirred for 0.5 h and warmed to 0° C. A 3 mL portion of this solution was added to a stirred solution of 3-[2-(4-difluoromethoxyphenyl)-2-oxo-acetyl]benzaldehyde (0.15 g, 0.49 mmol) in dry DME at 0° C. under nitrogen. After 10 min, the reaction mixture was quenched with saturated ammonium chloride, diluted with water and extracted with ethyl acetate. The combined extracts were dried over MgSO4 and concentrated in vacuo. Purification of the resultant residue by flash chromatography (30% to 70% ethyl acetate/petroleum ether) gave 1-[4-(difluoromethoxy)phenyl]-2-[3-(1,4-dihydroxybut-2-ynyl)phenyl]ethane-1,2-dione as a clear oil, 52 mg (29% yield). Using essentially the same procedure described in Example 1, step c, and employing 1-[4-(difluoromethoxy)phenyl]-2-[3-(1,4-dihydroxybut-2-ynyl)phenyl]ethane-1,2-dione (0.052 g, 0.14 mmol), the title compound was obtained as a slight brown foam, 0.031 g (52% yield), identified by NMR and mass spectral analyses. MS (ES+): 416 (M+H).
