Cesium carbonate → 4'-bromo-1'-((5-(trifluoromethyl)furan-2-yl)methyl)-5,6-dihydro-2H-spiro[benzofuro[6,5-b]furan-3,3'-indolin]-2'-one

Participants

Reaction Steps

To a stirred solution of 4′-bromo-5,6-dihydro-2H-spiro[benzofuro[6,5-b]furan-3,3′-indolin]-2′-one (0.64 g, 1.8 mmol) in 2-butanone (25 mL) was added cesium carbonate (1.75 g, 5.3 mmol) followed by 2-(bromomethyl)-5-(trifluoromethyl)furan (0.51 g, 2.2 mmol). The mixture was refluxed for 16 h, cooled to ambient temperature, filtered and concentrated in vacuo to dryness. The residue was subjected to column chromatography (hexanes/ethyl acetate from 3:1 to 1:1) to afford 4′-bromo-1′-((5-(trifluoromethyl)furan-2-yl)methyl)-5,6-dihydro-2H-spiro[benzofuro[6,5-b]furan-3,3′-indolin]-2′-one (0.82 g, 90%) as a colorless solid: mp 165-167° C.; 1H NMR (300 MHz, CDCl3) δ7.27-7.10 (m, 2H), 6.92 (td, J=6.9, 1.8 Hz, 1H), 6.77-6.70 (m, 1H), 6.44-6.33 (m, 3H), 5.15-4.96 (m, 2H), 4.91-4.76 (m, 2H), 4.53 (dt, J=8.6, 1.9 Hz, 2H), 2.98 (t, J=8.5 Hz, 2H); 13C NMR (75 MHz, CDCl3) δ177.3, 162.4, 162.2, 151.6, 143.4, 141.8 (q, J=43.0 Hz), 130.2, 127.7, 120.0, 119.7, 118.8 (q, J=267.1 Hz), 118.4, 117.0, 112.6, 109.5, 107.7, 92.9, 77.1, 72.4, 59.0, 37.0, 28.9; MS (ES+) m/z 505.8 (M+1), 507.8 (M+1).

Provenance & Evidence