Synthesis
Step 1: 1-bromo-2-vinylbenzene (3 g, 16.4 mmol) was dissolved in anhydrous THF (20 mL) under nitrogen protection and cooled to -78 °C. N-butyllithium (2.5 M hexane solution, 7.2 mL, 18.0 mmol) was slowly added dropwise, keeping the temperature below -70 °C. After the dropwise addition was completed, the reaction mixture was continued to be stirred at -70 °C for 1 hour. Subsequently, N,N-dimethylformamide (1.8 g, 24.6 mmol) was added to the reaction system and slowly warmed up to room temperature and continued stirring for 30 minutes. After the reaction was completed, the mixture was poured into water (20 mL) and the aqueous layer was extracted with ethyl acetate (20 mL x 2). The organic layers were combined, dried with anhydrous sodium sulfate and concentrated under reduced pressure to give 2-vinylbenzaldehyde (2.0 g, 91% yield).
References
[1] Journal of Organic Chemistry, 2011, vol. 76, # 7, p. 1979 - 1991
[2] Patent: US2017/37038, 2017, A1. Location in patent: Paragraph 0096; 0147; 0148
[3] Beilstein Journal of Organic Chemistry, 2014, vol. 10, p. 2222 - 2229
[4] Angewandte Chemie - International Edition, 2017, vol. 56, # 9, p. 2473 - 2477
[5] Angew. Chem., 2017, vol. 129, p. 2513 - 2517,5
