Tributylphosphine → 5-(benzyloxy)-1'-[(5-chloro-2-thienyl)methyl]spiro[1-benzofuran-3,3'-indol]-2'(1'H)-one

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 3-[5-(benzyloxy)-2-hydroxyphenyl]-1-[(5-chloro-2-thienyl)methyl]-3-hydroxymethyl-1,3-dihydro-2H-indol-2-one (2.71 g, 5.52 mmol) in anhydrous tetrahydrofuran (60 mL) was added dropwise tributylphosphine (1.39 g, 6.90 mmol). The solution was cooled to 0° C. and di-tert-butyl azodicarboxylate (1.59 g, 6.90 mmol) was added. The solution was stirred at 0° C. for 20 min then quenched with aqueous 10% hydrochloric acid (50 mL). The aqueous solution was extracted with ethyl acetate (3×100 mL), brine (3×50 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo to dryness. The residue was purified by flash column chromatography with ethyl acetate in hexanes (20%) to give 5-(benzyloxy)-1′-[(5-chloro-2-thienyl)methyl]spiro[1-benzofuran-3,3′-indol]-2′(1′H)-one (2.36 g, 90%) as a colorless solid: mp 132-135° C.; 1H NMR (300 MHz, DMSO-d6) 7.33-7.21 (m, 7H), 7.16-7.12 (m, 2H), 7.02 (ddd, J=7.4, 7.4, 1.0 Hz, 1H), 6.97 (d, J=3.8 Hz, 1H), 6.90-6.32 (m, 2H), 6.21 (d, J=2.3 Hz, 1H), 5.05 (ABq, 2H), 4.82 (s, 2H), 4.72 (ABq, 2H); 13C NMR (75 MHz, DMSO-d6) δ176.6, 155.0, 153.6, 141.9, 138.6, 137.4, 132.0 130.3, 129.4, 128.8, 128.2, 128.1, 127.9, 127.1, 124.3, 123.8, 116.6, 110.8, 110.0, 109.9, 79.4, 70.4, 58.1, 38.9; MS (ES+) m/z 476.3 (M+1), 474.3 (M+1).

Provenance & Evidence