3,4-Dibromothiophene → HCID 57734457, compound

Participants

Reaction Conditions

Reaction Steps

Into a 250 mL 4 necked RB flask equipped with a magnetic stirring bar, thermometer, rubber septum, argon inlet and reflux condenser with argon outlet (tubed to a silicon oil bubbler) is added 55.0 g (229 mmol) of 3,4-dibromothiophene, 15.6 g of triethylamine, 9.75 g (68.5 mmol) of trimethylsiloxy-1-butyne, 170 mg of triphenylphosphine, 140 mg of copper iodide and 490 mg of dichlorobis(triphenylphosphine) palladium(II). The mixture is heated with a silicon oil bath to 60° C. under argon with stirring for 2 hrs. The cooled mixture is then concentrated on a rotary evaporator at reduced pressure and the residue taken up in 200 mL of hexanes and washed with 2×25 mL of water and the pentane phase dried over sodium sulfate and then concentrated on a rotary evaporator. The residue was chromatographed through neutral silica gel eluted with 2/1 methylenechloride/hexanes to yield 4.8 g of 3-bromo-4(trimethylsiloxybutynyl)thiophene as a light yellow oil which was used directly to prepare 2-hydroxyethylselenolo[2,3-c]thiophene.

Provenance & Evidence