Reaction Steps
A mixture of spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one (1.99 g, 7.08 mmol), 4-methoxybenzyl chloride (1.30 mL, 9.6 mmol), potassium iodide (0.17 g, 0.99 mmol) and cesium carbonate (4.68 g, 14.4 mmol) in 2-butanone (45 mL) was stirred at reflux under nitrogen for 16 h. The reaction was cooled, diluted with ethyl acetate and filtered through Celite. The filtrate was concentrated under reduced pressure and the residue was purified by flash column chromatography with hexanes/ethyl acetate (4:1) to afford 1′-(4-methoxybenzyl)spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one (2.52 g, 89%) as a colorless solid: mp 147-148° C. (hexanes); 1H NMR (300 MHz, CDCl3) δ7.28 (d, J=8.7 Hz, 2H), 7.21 (ddd, J=7.8, 7.5, 1.2 Hz, 1H), 7.16 (dd, J=7.5, 0.6 Hz, 1H), 7.02 (ddd, J=7.7, 7.4, 1.0 Hz, 1H), 6.88 (d, J=8.7 Hz, 2H), 6.83 (d, J=7.8 Hz, 1H), 6.53 (s, 1H), 6.13 (s, 1H), 5.88 (d, J=1.2 Hz, 1H), 5.87 (d, J=1.2 Hz, 1H), 5.02 (d, J=15.3 Hz, 1H), 4.97 (d, J=9.0 Hz, 1H), 4.76 (d, J=15.3 Hz, 1H), 4.69 (d, J=9.0 Hz, 1H), 3.79 (s, 3H); MS (ES+) m/z 402.2 (M+1).
