Synthesis
The general procedure for the synthesis of tert-butyl [1-(4-bromophenyl)-cyclopropyl]carbamate from 1-(4-bromophenyl)cyclopropan-1-amine and di-tert-butyl dicarbonate was as follows: in a 100-mL round-bottom flask, 1-(4-bromophenyl)cyclopropan-1-amine (1 g, 4.48 mmol, 1.00 equiv) and di-tert-butyl dicarbonate (3.1 g, 13.49 mmol , 3.01 eq.) were dissolved in tetrahydrofuran (20 mL). Subsequently, an aqueous solution of sodium bicarbonate (5 g, 59.5 mmol, 13.29 eq.) was slowly added to the reaction system (10 mL) at room temperature. The reaction mixture was stirred overnight at room temperature. After completion of the reaction, the reaction mixture was extracted with ethyl acetate (3 x 10 mL), the organic layers were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure to remove the solvent. The residue was purified by silica gel column chromatography using ethyl acetate/petroleum ether (10% to 50% gradient) as eluent to afford tert-butyl [1-(4-bromophenyl)-cyclopropyl]carbamate (1.47 g, 99%) as a light yellow solid. Mass spectrometry (MS) analysis showed: m/z = 255.7 [M+H-56]+.
References
[1] Patent: US2016/96834, 2016, A1. Location in patent: Paragraph 0390
[2] Patent: US2012/108574, 2012, A1. Location in patent: Page/Page column 113
[3] Patent: WO2016/57762, 2016, A1. Location in patent: Page/Page column 30
[4] Patent: WO2016/102672, 2016, A2. Location in patent: Page/Page column 115
