Synthesis
1. Boc protection reaction: 4-bromobenzylamine (40.0 g, 217.0 mmol) was dissolved in THF (150 mL), di-tert-butyl dicarbonate (46.0 g, 217 mmol) was added, and the reaction was stirred at room temperature for 1 hour. After completion of the reaction, the mixture was concentrated in vacuum to give the crude product. The crude product was purified by silica gel column chromatography (eluent: 80:20 hexane/EtOAc) to afford the Boc-protected amine (63.0 g, 95% yield) as a white solid.
2. Borylation reaction: Boc-protected aryl bromide (30.0 g, 98.0 mmol) was dissolved in DMSO (100 mL), and bis(pinacolato)diboron (30.0 g, 118 mmol), KOAc (30.0 g, 306 mmol), and PdCl2(dppf) (0.2 mmol) were added sequentially. The reaction mixture was heated to 85 °C and stirred for 12 hours. After completion of the reaction, it was diluted with EtOAc (250 mL) and washed sequentially with water (2 x 150 mL) and brine (100 mL). The organic layer was dried with anhydrous Na2SO4 and concentrated in vacuum to obtain the crude product. Purification by silica gel column chromatography (eluent: 80:20 hexane/EtOAc) afforded the target compound (31.0 g, 97% yield) as a white solid.ESI-MS (M+H)+: 334.
References
[1] Patent: WO2015/89327, 2015, A1. Location in patent: Paragraph 0336
[2] Chemical Communications, 2013, vol. 49, # 30, p. 3110 - 3112
[3] Angewandte Chemie - International Edition, 2013, vol. 52, # 33, p. 8666 - 8670
[4] Angew. Chem., 2013, vol. 125, # 33, p. 8828 - 8832,5
[5] Patent: US2007/179115, 2007, A1. Location in patent: Page/Page column 19
