A stirred solution of 3-[2-(4-difluoromethoxyphenyl)-2-oxo-acetyl]-benzaldehyde (0.1 g, 0.33 mmol) in dry DME at 0° C. under nitrogen was treated over 10 min with 0.5 M 1-propynyl magnesium bromide in THF. The reaction was stirred for 0.5 h, 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 (20% to 40% ethyl acetate/petroleum ether) gave 1-(4-difluoromethoxyphenyl)-2-[3-(1-hydroxybut-2-ynyl)phenyl]ethane-1,2-dione as a clear oil, 55 mg (49% yield). Using essentially the same procedure described as described in Example 1, step c, and employing 1-(4-difluoromethoxyphenyl)-2-[3-(1-hydroxy-but-2-ynyl)phenyl]-ethane-1,2-dione (0.055 g, 0.16 mmol), the title product was obtained as a slight yellow foam, 0.044 g (69% yield), identified by NMR and mass spectral analyses. MS (ES+): 400 (M+H).
