At room temperature, potassium hydroxide (330 mg) and tetrahexylammonium chloride (190.1 mg) were dissolved in DMF (15 ml). After adding a solution (5 ml) of (2S)-2-(2,3,4-trifluoroanilino)propanol (1 g, 99.8% ee) and diethylethoxymethylenemalonate (2.09 g) in DMF, the resultant mixture was stirred for 1 hour. After adding water, the liquid reaction mixture was extracted with a solvent mixture of ethyl acetate and n-hexane (3:2). The organic layer was washed with water and dried over anhydrous magnesium sulfate. After evaporating the solvent, IPE was added to the obtained residue and the mixture was stirred at 0° C. for 1 hour. The crystals thus precipitated were collected by filtration and the moist product thus obtained was dried under reduced pressure. Thus, the title compound (1.65 g, 99.8% ee) was obtained as colorless crystals. The 1H-NMR and IR spectral data of this product was identical with those of the compound obtained in Example 63.
