Carbon tetrabromide → methyl 7-(benzenesulfonylmethyl)-4H-furo[2,3-c]chromene-6-carboxylate

Participants

Reaction Steps

Carbon tetrabromide (0.116 g) was added to a solution of methyl 6-(benzenesulfonylmethyl)-2-hydroxy-3-(2-hydroxymethylfuran-3-yl)-benzoate (Intermediate 19, 0.1 g) and triphenyl phosphine (0.09 g) in DCM (3 mL) and the resultant solution was stirred at room temperature for 2 hours. The mixture was evaporated to dryness and the residue was dissolved in DMF (2 mL) and cesium carbonate (0.163 g) was added. The mixture was stirred for 1 hour at room temperature, then at 50° C. for 15 minutes. After cooling, the mixture was partitioned between ethyl acetate and water, the organic layer was separated, dried (Na2SO4) and filtered. The filtrate was evaporated to dryness and the residue was purified by chromatography on silica, eluting with a mixture of ethyl acetate and cyclohexane (25%) to give methyl 7-(benzenesulfonylmethyl)-4H-furo[2,3-c]chromene-6-carboxylate (0.019 g).

Provenance & Evidence