Reaction Steps
A mixture of 1′-pentylspiro[indeno[5,6-d][1,3]dioxole-5,3′-indole]-2′,7(1′H,6H)-dione (0.04 g, 0.11 mmol), triethylsilane (1.50 mL) and trifluroacetic acid (2.00 mL, excess) was stirred at ambient temperature overnight. The mixture was concentrated in vacuo to dryness. The residue was subjected to flash column chromatography to afford the title compound (0.02 g, 47%) as an oil: 1H NMR (300 MHz, CDCl3) δ 7.25 (td, 1H), 7.06-6.95 (m, 2H), 6.88 (d, 1H), 6.77 (s, 1H), 6.05 (s, 1H), 5.88-5.82 (m, 2H), 3.81-3.60 (m, 2H), 3.37-3.24 (m, 1H), 3.13-3.01 (m, 1H), 2.70-2.59 (m, 1H), 2.44-2.32 (m, 1H), 1.76-1.64 (m, 2H), 1.39-1.28 (m, 4H), 0.88 (t, 3H); 13C NMR (75 MHz, CDCl3) δ 179.5, 147.9, 147.0, 142.9, 138.2, 136.7, 134.7, 128.1, 123.5, 122.6, 108.3, 105.3, 103.6, 101.2, 59.9, 40.0, 38.3, 31.6, 29.0, 27.1, 22.6, 14.0; MS (ES+) m/z 372.1 (M+23), 350.1 (M+1).
