3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-(triisopropylsilyl)-1H-pyrrole

87630-36-2

25015-63-8

365564-11-0

To a stirred solution of 3-bromo-1-(triisopropylmethylsilyl)pyrrole (6.50 g, 21.50 mmol) and pinacolborane (4.13 g, 32.25 mmol) in toluene (120 mL) was sequentially added PdCl2(ACN)2 (0.45 g, 1.72 mmol), dicyclohexyl (2',6'-dimethoxybiphenyl-2-yl)phosphine (2.65 g, 6.45 mmol) and triethylamine (6.53 g, 64.50 mmol). The reaction mixture was degassed twice with nitrogen and subsequently heated to 90 °C and kept for 16 hours. The progress of the reaction was monitored by thin layer chromatography (TLC) and after confirming complete consumption of the raw materials the reaction was stopped and cooled to room temperature. The reaction mixture was diluted with ethyl acetate (200 mL), filtered through a pad of diatomaceous earth and the filtrate was concentrated under reduced pressure. The residue was purified by column chromatography (eluent ratio: ethyl acetate/hexane from 1/200 to 1/50) to afford the target product 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-[tris(1-methylethyl)methanesilyl]-1H-pyrrole (3.50 g, 46% yield) as a white solid.