863578-21-6

823-57-4

25015-63-8

863578-21-6

Step 1: Preparation of 5-chloro-2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline To a solution of 2-bromo-5-chloroaniline (20.0 g, 96.9 mmol) in 1,4-dioxane (200 ml) was sequentially added triethylamine (54.0 ml, 487 mmol) and [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride dichloromethane complex (3.96 g, 4.84 mmol) under nitrogen protection. Subsequently, 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (42.3 ml, 290 mmol) was slowly added dropwise. The reaction mixture was stirred at 100 °C for 10.5 hours. After completion of the reaction, the mixture was cooled to room temperature and filtered through diatomaceous earth. The filtrate was quenched by dropwise addition of methanol (25 ml) at 0°C. The solvent was removed by concentration under reduced pressure and the resulting crude product was purified by silica gel column chromatography (eluent: hexane/ethyl acetate = 20:1) to afford the target product 5-chloro-2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline (16.5 g, 65% yield). 1H-NMR (400 MHz, DMSO-d6): δ (ppm) 7.28 (1H, d, J=6.0 Hz), 6.59 (1H, d, J=1.2 Hz), 6.43 (1H, dd, J=6.3,1.5 Hz), 5.70 (2H, s), 1.24 (12H, s).