Trifluoroacetic acid → 3-(4-Bromo-benzyl)-2-butyl-benzofuran

Participants

Reaction Conditions

Reaction Steps

A solution of (4-bromo-phenyl)-(2-butyl-benzofuran-3-yl)-methanone (2.25 g, 6.32 mmol) in ethanol (20 mL, 0.3 M) was cooled to 0° C. and treated with NaBH4 (0.263 g, 1.1 equiv, 6.95 mmol). After stirring for 1 h, the mixture was poured into a 50% ether in water solution (200 mL). After separation, the aqueous layer was extracted with ether (50 mL) and the combined organic layers were washed with water, sat'd aq NaCl, dried over anhydrous MgSO4, filtered and concentrated in vacuo. The resulting alcohol was subsequently disolved in dry dichloromethane (50 mL), cooled to 0° C. and treated with triethylsilane (2.0 mL, 2.0 equiv., 12.64 mmol) dropwise via syringe. After stirring an additional 5 min, trifluoroacetic acid (2.43 mL, 5.0 equiv., 31.6 mmol) was added over 2 min and the mixture was stirred for 3 h. Once complete, the solution was washed with water, sat'd aq NaCl, dried over anhydrous MgSO4, filtered and concentrated in vacuo. Purification by flash column chromatography (0-2% ethyl acetate in heptane) afforded 3-(4-bromo-benzyl)-2-butyl-benzofuran as a pale yellow oil (1.34 g, 63%).

Provenance & Evidence