Boron tribromide → 1-(1-Benzofuran-3-yl)ethan-1-one

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of 1-(2-methoxyphenyl)propan-2-one (10 g) and dimethylformamide dimethyl acetal (17.8 g) was stirred at 80° C, under nitrogen for 4 hours, then concentrated in vacuo to leave a viscous oil. The oil was disolved in dichloromethane (80 ml), and the solution was stirred and cooled in an ice-bath while boron tribromide (1M solution in dichloromethane; 104 ml) was added dropwise over 15 minutes. When the addition was complete, the mixture was stirred, with ice-cooling, for a further 1.5 hours, then it was poured into an excess of ice and saturated aqueous sodium hydrogen carbonate solution. The product was extracted into dichloromethane (3×200 ml) and the combined extracts were washed with water (2×200 ml), dried (Na2SO4), and the solvent removed in vacuo to leave 3-acetylbenzo[b]furan as a dark red oil (4.25 g).

Herkunft & Nachweise