Ethylene Glycol → 5-(2-Ethyl-1,3-dioxolan-2-yl)benzofuran

Reaction equation

[O:1]1[C:5]2[CH:6]=[CH:7][C:8]([C:10](=[O:13])[CH2:11][CH3:12])=[CH:9][C:4]=2[CH:3]=[CH:2]1.[CH2:14](O)[CH2:15][OH:16].CC1C=CC(S(O)(=O)=O)=CC=1>C1(C)C=CC=CC=1>[CH2:11]([C:10]1([C:8]2[CH:7]=[CH:6][C:5]3[O:1][CH:2]=[CH:3][C:4]=3[CH:9]=2)[O:16][CH2:15][CH2:14][O:13]1)[CH3:12]

Participants

Procedure

A solution of 1-(benzofuran-5-yl)propan-1-one (650 mg, 1.0 eq), ethane-1,2-diol (3.5 g, 15.0 eq) and 4-methylbenzenesulfonic acid (65 mg, 0.1 eq) in 20 mL toluene was refluxed for 72 h, cooled, quenched with sat. NaHCO3 (aq) and extracted with EtOAc. The extract was washed with brine, dried, concentrated, and purified by column chromatography to give the desired product (710 mg, 87%). 1H NMR (400 MHz, CDCl3) δ 7.69 (d, J=2.0 Hz, 1H), 7.62 (d, J=2.4 Hz, 1H), 7.45 (d, J=8.4 Hz, 1H), 7.39 (dd, J=8.4 Hz, 1.6 Hz, 1H), 6.76 (dd, J=2.4 Hz, 0.4 Hz, 1H), 4.02-4.05 (m, 2H), 3.78-3.81 (m, 2H), 1.96 (q, J=7.2 Hz, 2H), 0.89 (t, J=7.2 Hz, 3H).