1-Isopropoxy-2-vinylbenzene was synthesized as follows: first, 15.65 g of methyltriphenylphosphonium bromide was suspended in 100 mL of dry tetrahydrofuran (THF), and 19.0 mL of n-butyllithium (n-BuLi, 2.5 M n-hexane solution) was slowly added to this suspension at room temperature. The reaction mixture was then transformed into an orange colored solution with continuous stirring for 4 hours. Subsequently, 6.00 g (36.5 mmol) of 2-isopropoxybenzaldehyde dissolved in 25 mL of anhydrous THF was slowly added dropwise under stirring. Upon completion of the dropwise addition, the formation of a white precipitate was observed in the reaction system. After continued stirring of the reaction mixture for 1 h, vacuum concentration was carried out to give a viscous yellow oil. The crude product was purified by a short silica gel column (eluent: heptane) followed by vacuum distillation to give 3.66 g of 1-isopropoxy-2-vinylbenzene as a colorless liquid. The structure of the product was confirmed by 1H-NMR (300 MHz, CDCl3) and GC-MS analysis: 1H-NMR (300 MHz, CDCl3) δ 1.27 (d, J = 6.1 Hz, 6H), 4.47 (m, 1H), 5.15 (dd, J1 = 11.2 Hz, J2 = 1.6 Hz, 1H), 5.65 (dd, J1 = 17.8 Hz, J2 = 1.6 Hz, 1H), 6.78-6.88 (m, 2H), 6.92-7.05 (m, 1H), 7.08-7.16 (m, 1H), 7.40 (dd, J1 = 7.6 Hz, J2 = 1.7 Hz, 1H); GC-MS showed purity of >99.0%, MS (EI): 162.
