Imidazole → 6-{[tris(1-methylethyl)silyl]oxy}spiro[1-benzofuran-3,3'-indol]-2'(1'H)-one

Participants

Reaction Steps

To a solution of 6-hydroxyspiro[1-benzofuran-3,3′-indol]-2′(1′H)-one (3.0 g, 11.8 mmol) in anhydrous N,N-dimethylformamide (30 mL) under nitrogen were added imidazole (1.97 g, 28.9 mmol) and triisopropylsilyl chloride (6.03 mL, 28.5 mmol). The reaction mixture was stirred at ambient temperature for 16 h. The reaction mixture was concentrated in vacuo to dryness. The residue was extracted twice with ethyl acetate (50 mL), the combined organic phases were dried over sodium sulfate, and the filtrate was concentrated and purified by flash chromatography with 30% ethyl acetate in hexanes to give 6-{[tris(1-methylethyl)silyl]oxy}spiro[1-benzofuran-3,3′-indol]-2′(1′H)-one (2.68 g, 69% yield) as colorless solid: 1H NMR (300 MHz, CDCl3) δ8.48-8.08 (br, 1H), 7.29-6.90 (m, 4H), 6.10 (d, J=8.1 Hz, 1H), 6.50 (d, J=2.1 Hz, 1H), 6.35 (dd, J=8.1, 2.1 Hz, 1H), 4.96 (d, J=9.0 Hz, 1H), 4.69 (d, J=9.0 Hz, 1H), 1.34-0.98 (m, 21H).

Provenance & Evidence