Cesium carbonate → 1'-benzhydryl-6-(benzyloxy)-2H-spiro[benzofuran-3,3'-indolin]-2'-one

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Reaction Steps

To a stirred solution of 3-[4-(benzyloxy)-2-hydroxyphenyl]-1-(diphenylmethyl)-1,3-dihydro-2H-indol-2-one (7.4 g, 14.8 mmol), chloroiodomethane (2.7 mL, 37.0 mmol) in anhydrous tetrahydrofuran (200 mL) was added cesium carbonate (15.4 g, 47.4 mmol) under argon. The mixture was stirred at ambient temperature for 16 h, then filtered through a pad of celite. The filtrate was concentrated under vacuum. The residue was purified by column chromatography (ethyl acetate/hexanes, 1/5) followed by the treatment with diethyl ether/hexanes to afford 6-(benzyloxy)-1′-(diphenylmethyl)spiro[1-benzofuran-3,3′-indol]-2′(1′H)-one (4.1 g, 55%) as a colorless solid: 1H NMR (300 MHz, CDCl3) δ 7.42-7.25 (m, 15H), 7.16-7.09 (m, 1H), 7.07-6.90 (m, 3H), 6.62-6.38 (m, 4H), 5.03-4.90 (m, 3H), 4.73 (d, J=9.0 Hz, 1H); MS (ES+) m/z 510.1 (M+1).

Provenance & Evidence