To a 250 mL oven-dried round-bottom flask equiped with a stirring bar, isopropyltriphenylphosphonium iodide (6.0 g, 14 mmol,1.2 equiv) and anhydrous THF (70 mL, 0.2 M) were added. The reaction flaskwas capped with rubber septum and three cycles of evacuate-refill with nitrogen were performed, then the reaction mixture was cooled to 0 °C. n-BuLi (2.5 M, 5.6 mL, 14 mmol, 1.2 equiv) was added dropwise by syringe and the reaction mixture was stirred at this temperature for 30 min. A solution of aldehyde 11 (1577 mg, 11.60 mmol, 1.0 equiv) in THF (20 mL) was added by syringe and the reaction mixture was allowed to warm to room temperature, and then stirred for 16 h. After the reaction reached completion according to the TLC analysis, the reaction mixture was quenched by sat. NH4Cl (30 mL) and extracted with EtOAc (100mL) for 3 times. The combined organic layers were washed with H2O2 (10 wt% in water, 10 mL) and brine (20 mL), dried over Na2SO4, and filtered. After that, the mixture was concentrated under reduced pressure, the crude residue was purified by column chromatography (Pentant : EtOAc = 50: 1 to 10: 1) to afford the desired alkene 12 as colorless oil.