2,3-Dihydro-1-benzofuran-6-ol → 7-chloro-1-(diphenylmethyl)-3-hydroxy-3-(6-hydroxy-2,3-dihydro-1-benzofuran-5-yl)-1,3-dihydro-2H-indol-2-one

Participants

Reaction Steps

To a cooled (0° C.) solution of 2,3-dihydrobenzofuran-6-ol (0.52 g, 3.8 mmol) in anhydrous tetrahydrofuran (25 mL) was added isopropylmagnesium chloride (2.1 mL, 2 M solution in tetrahydrofuran, 4.2 mmol). The resultant suspension was stirred at 0° C. for 0.5 h and followed by the addition of 7-chloro-1-(diphenylmethyl)-1H-indole-2,3-dione (2.11 g, 15.5 mmol) in one portion. The reaction mixture was stirred at ambient temperature for 3 h and concentrated in vacuo. The crude product was purified by column chromatography with ethyl acetate in hexanes (0% to 50% gradient) to afford 7-chloro-1-(diphenylmethyl)-3-hydroxy-3-(6-hydroxy-2,3-dihydro-1-benzofuran-5-yl)-1,3-dihydro-2H-indol-2-one (7.12 g, 95%) as a colorless solid: 1H NMR (300 MHz, DMSO-d6) δ9.43 (s, 1H), 7.56-7.18 (m, 13H), 6.99-6.86 (m, 2H), 6.60 (s, 1H), 6.08 (s, 1H), 4.56 (t, J=8.6 Hz, 2H), 3.10 (t, J=8.6 Hz, 2H).

Provenance & Evidence