*3.4. General Procedure of Wittig Reaction* (**3aa-ad, 3ba-bd, 3ca-cd, 3ea**)

To a stirred solution of the corresponding benzyltriphenylphosphonium bromide (0.098 mmol, 1.5 equiv.) in THF (2.0 mL) was slowly added *n*-butyllithium (2.5 M in hexane, 0.036 mL, 0.091 mmol, 1.4 equiv.) at 0 ◦C under argon atmosphere. After stirring for 1 h at the same temperature, a solution of the corresponding aldehyde **7** (0.065 mmol, 1.0 equiv.) in THF (1.0 mL) was added. Then, the reaction temperature was raised to 50 ◦C. After 4 h, the reaction mixture was cooled to rt and diluted with sat. aq. NH4Cl (30 mL) and EtOAc (70 mL). The organic layer was separated, dried over Na2SO4, filtered, and concentrated under reduced pressure. The crude residue was purified by column chromatography to afford 3-(1,3-diarylallyliden)oxindole **3**.
