To a stirred solution of 1-(9H-carbazol-9-yl)-3-((furan-2-ylmethyl)amino)propan-2-ol (1.80 g, 5.6 mmol) and imidazole (1.912 g, 28.1 mmol) in anhydrous methylene chloride (50 mL) was added tert-butyldimethylsilyl chloride (2.117 g, 14.0 mmol). The reaction mixture was stirred overnight at 70° C. The reaction mixture was washed with saturated aqueous sodium chloride and saturated aqueous sodium carbonate, dried (anhydrous sodium sulfate), filtered, and concentrated. The residue was purified by silica gel column chromatography (0-40% ethyl acetate in hexanes) to afford the product as a thick oil (2.4 g, 98%). 1H NMR (300 MHz, CDCl3) δ 8.08 (d, 2H, J=7.8 Hz), 7.53-7.40 (m, 4H), 7.37 (d, 1H, J=1.5 Hz), 7.22 (t, 2H, J=7.2 Hz), 6.32 (dd, 1H, J=3.3, 1.8 Hz), 6.16 (d, 1H, J=3.3 Hz), 4.56 (dd, 1H, J=14.4, 6.0 Hz), 4.41-4.22 (m, 2H), 3.85 and 3.75 (dd, 2H, J=14.4, 14.4 Hz), 2.74 (dd, 1H, J=12.0, 4.5 Hz), 2.61 (dd, 1H, J=12.0, 3.6 Hz), 1.60 (br s, 2H), 0.80 (s, 9H), −0.13 (s, 3H), −0.42 (s, 3H). ESI m/z: 435.2 [M+H].
