In a stream of argon, to 70 ml of tetrahydrofuran was added 10.45 g of phenyllithium (19% solution in dibutylether) (23.6 mmol), and 8.09 g (20.5 mmol) of 2-thenyl triphenylphosphonium chloride was added thereto under cooling. To this mixture was added dropwise 4.92 g (21.0 mmol) of 4-(dibutylamino)benzaldehyde. The mixture was stirred at the same temperature for 1 hour. After the reaction mixture was poured into water, extraction with toluene, washing with a saturated saline solution, drying over anhydrous sodium sulfate, and concentration were performed. The residue was purified by silica gel column chromatography to give an orange liquid. This liquid was dissolved in 200 ml of toluene and 200 mg of iodine was added thereto. After stirred at room temperature for 15 minutes, the mixture was added to water and the phases were separated. The organic layer was dried over anhydrous sodium sulfate and concentrated. The residue was purified by silica gel column chromatography to give 6.09 g of an orange oily matter (yield: 94.8%).
