To a mixture of 124E (1.97 g, 9.0 mmol) and sodium iodide (0.27 g, 1.8 mmol) in 70% H2SO4 (30 mL) at 110°C under nitrogen was added acrolein (1.1 mL, 13.6 mmol) via syringe pump (1 mL/h). The reaction was stirred for another 30 min at 110°C after complete addition. After cooling to room temperature, the reaction mixture was diluted with ice water (50 mL) then added to an aqueous solution (500 mL) of Na2CO3 (60 g) slowly. This mixture was extracted with chloroform (3x200 mL). The combined organic phases were dried over Na2SO4, filtered and concentrated. The residue was purified by flush chromatography (hexanes/ethyl acetate) to give 124F as a solid.