Synthesis
To a stirred mixture of bromobenzene (0.7 mL, 6.5 mmol) and monoethyl oxalyl chloride (0.7 mL, 6.5 mmol) in dichloromethane (12 mL) was added aluminum trichloride (1.7 g, 12.5 mmol) in one batch. The reaction mixture was stirred at 0°C for 30 minutes before slowly warming to room temperature and continuing to stir for 18 hours. After completion of the reaction, the mixture was carefully poured into concentrated hydrochloric acid at 0°C to quench the reaction. Subsequently, the mixture was extracted with dichloromethane (3 × 100 mL). The organic layers were combined, washed with saturated saline (100 mL), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (eluent: ethyl acetate/petroleum ether = 1:20) to afford ethyl 4-bromophenylglyoxylate (1.0 g, 60% yield) as a yellow oil. Mass spectrometry (ESI+) analysis: C10H9BrO3 theoretical value [M+H]+ 256, measured value 257, 259 [M+H]+.
References
[1] Journal of Organic Chemistry, 1996, vol. 61, # 18, p. 6407 - 6415
[2] Tetrahedron Letters, 2006, vol. 47, # 16, p. 2675 - 2678
[3] Chemical Science, 2018, vol. 9, # 48, p. 8930 - 8936
[4] Patent: US2016/31892, 2016, A1. Location in patent: Paragraph 0156-0158
[5] Journal of Organic Chemistry, 2008, vol. 73, # 10, p. 3842 - 3847
