Reaktionsschritte
To a stirred solution of spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one (0.84 g, 3.0 mmol) and (1-isopropyl-2,5-dimethyl-1H-pyrrol-3-yl)methanol (0.50 g, 3.0 mmol) in anhydrous tetrahydrofuran (15 mL) was added dropwise tributylphosphine (0.90 g, 1.5 mmol). The solution was cooled to 0° C. and diethyl azodicarboxylate (0.78 g, 4.5 mmol) was added. The solution was stirred at ambient temperature for 16 h then quenched with saturated ammonium chloride (50 mL). The aqueous solution was extracted with ethyl acetate (200 mL), dried on magnesium sulfate, filtered and concentrated in vacuo to dryness. The residue was purified by flash chromatography with ethyl acetate in hexanes (15% to 50% gradient) to afford 1′-{[2,5-dimethyl-1-(1-methylethyl)-1H-pyrrol-3-yl]methyl}spiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one (0.32 g, 24%) as a colorless solid: mp 169-171° C.; 1H NMR (300 MHz, CDCl3) δ 7.27-7.20 (m, 1H), 7.11 (d, J=7.5 Hz, 1H), 7.02-6.95 (m, 2H), 6.49 (s, 1H), 6.09 (s, 1H), 5.85-5.82 (m, 2H), 5.77 (br s, 1H), 4.77 (ABq, 2H), 4.69 (ABq, 2H), 4.37 (sep, J=7.0 Hz, 1H), 2.33 (s, 3H), 2.22 (s, 3H), 1.43 (d, J=7.0 Hz, 6H); 13C NMR (75 MHz, CDCl3) δ194.7, 177.2, 155.9, 148.7, 142.9, 142.2, 132.5, 128.7, 127.0, 125.5, 123.6, 122.9, 119.9, 113.0, 109.6, 107.6, 103.2, 101.4, 93.5, 80.5, 58.2, 47.3, 37.0, 22.2, 14.1, 11.5; MS (ES+) m/z 431.20 (M+1).
