Synthesis
5-Bromovaleric acid (5 g, 27.62 mmol) was dissolved in anhydrous dichloromethane (DCM), and the solution was brought to room temperature and stirred under cooling in an ice bath. N,N'-dimethylaminopyridine (DMAP, 1.68 g, 13.75 mmol) and dicyclohexylcarbodiimide (DCC, 6.83 g, 33.15 mmol) were added sequentially. After half an hour of reaction, tert-butanol (15.8 ml, 165.75 mmol) was added to the mixture. The reaction solution was stirred at room temperature overnight. After completion of the reaction, the reaction mixture was diluted with dichloromethane and washed sequentially with water and brine. The organic layer was separated, dried over anhydrous sodium sulfate and evaporated under reduced pressure to remove the solvent. The crude product was purified by silica gel column chromatography with hexane-ethyl acetate (1%) as eluent to give pure tert-butyl 5-bromopentanoate 4.1 g (62.6% yield) as a light yellow liquid.
References
[1] Patent: WO2015/6740, 2015, A2. Location in patent: Page/Page column 182; 183
[2] Patent: WO2016/154241, 2016, A1. Location in patent: Paragraph 670; 671
[3] European Journal of Organic Chemistry, 2018, vol. 2018, # 37, p. 5180 - 5192
[4] Patent: KR101569966, 2015, B1. Location in patent: Paragraph 0145; 0146
[5] Patent: WO2011/53519, 2011, A1. Location in patent: Page/Page column 27-28
