2-(2,2-dibromoethenyl)furan

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 5.9 g (25 mmoles) of 1,1-dibromo-2-(furan-2-yl)ethylene in 124 mL of anhydrous THF at −20° was added dropwise 31.0 mL of 1.6 M n-butyllithium in hexanes (50 mmoles). This solution was allowed to warm to ambient temperature over a period of 30 min, after which time it was cooled to −50°. 4,6-Dichloro-4-(trifluoromethyl)-2H-3,1-benzoxazin-2-one (2.65 g, 9.27 mmoles) was added in one portion, and the resulting solution was allowed to warm to −35° over 40 min. The reaction was quenched by the addition of aqueous ammonium chloride, and this mixture was poured onto water and extracted twice with ethyl acetate. The combined extracts were washed with brine, dried over sodium sulfate, and evaporated. The crude product was purified by column chromatography on silica gel (elution with 15% and 30% ethyl acetate in hexanes) affording 3.5 g of a solid which was recrystallized from ethyl acetate/hexanes to afford 3.03 g (95.7%) of the title compound. after which time it was cooled to −50° to warm to −35° over 40 min The reaction was quenched by the addition of aqueous ammonium chloride this mixture was poured onto water extracted twice with ethyl acetate The combined extracts were washed with brine dried over sodium sulfate evaporated The crude product was purified by column chromatography on silica gel (elution with 15% and 30% ethyl acetate in hexanes)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 5.9 g (25 mmoles) of 1,1-dibromo-2-(furan-2-yl)ethylene in 124 mL of anhydrous THF at -20° was added dropwise 31.0 mL of 1.6 M n-butyllithium in hexanes (50 mmoles). This solution was allowed to warm to ambient temperature over a period of 30 min, after which time it was cooled to -50°. 4,6-Dichloro-4-(trifluoromethyl)-2H-3,1-benzoxazin-2-one (2.65 g, 9.27 mmoles) was added in one portion, and the resulting solution was allowed to warm to -35° over 40 min. The reaction was quenched by the addition of aqueous ammonium chloride, and this mixture was poured onto water and extracted twice with ethyl acetate. The combined extracts were washed with brine, dried over sodium sulfate, and evaporated. The crude product was purified by column chromatography on silica gel (elution with 15% and 30% ethyl acetate in hexanes) affording 3.5 g of a solid which was recrystallized from ethyl acetate/hexanes to afford 3.03 g (95.7%) of the title compound. after which time it was cooled to -50° to warm to -35° over 40 min The reaction was quenched by the addition of aqueous ammonium chloride this mixture was poured onto water extracted twice with ethyl acetate The combined extracts were washed with brine dried over sodium sulfate evaporated The crude product was purified by column chromatography on silica gel (elution with 15% and 30% ethyl acetate in hexanes)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 9.6 g (29 mmol) of carbon tetrabromide in 120 mL of dry me hylene chloride at 0° was added 15.2 g (58 mmol) of tripheiiylphosphine. After 15 min 3.0 mL (22.5 mmol) of triethylamine was added, and after stirring another 5 min at 0°, the reaction mixture was cooled to -780°. At this temperature 1.50 mL (22.5 mmol) of 2-furaldehyde was added quickly dropwise, and after addition was complete, the mixture was stirred a -70° for 30 min. The reaction mixture was poured onto a rapidly stirring saturated solution of sodium bicarbonate in water. The methylene chloride phase was removed and the aqueous layer was extracted with additional methylene chloride. The combined extracts were evaporated to a solid which was stirred in 500 mL of hexanes for 2 h. After filtration, the filtrate was concentrated to a volume of 50 mL and the filtered again to remove precipitated solid. Final evaporation of the filtrate afforded 3.1 g (58%) of the title compound. was added 15.2 g (58 mmol) of tripheiiylphosphine the reaction mixture was cooled to -780° after addition the mixture was stirred a -70° for 30 min The methylene chloride phase was removed the aqueous layer was extracted with additional methylene chloride The combined extracts were evaporated to a solid which was stirred in 500 mL of hexanes for 2 h After filtration the filtrate was concentrated to a volume of 50 mL the filtered again to remove precipitated solid Final evaporation of the filtrate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 5.9 g (25 mmoles) of 1,1-dibromo-2-(furan-2-yl)ethylene in 124 mL of anhydrous THF at -20° was added dropwise 31.0 mL of 1.6M n-butyllithium in hexanes (50 mmoles). This solution was allowed to warm to ambient temperature over a period of 30 min, after which time it was cooled to -50°. 4,6-Dichloro-4-(trifluoromethyl)-2H-3,1-benzoxazin-2-one (2.65 g, 9.27 mmoles) was added in one portion, and the resulting solution was allowed to warm to -35° over 40 min. The reaction was quenched by the addition of aqueous ammonium chloride, and this mixture was poured onto water and extracted twice with ethyl acetate. The combined extracts were washed with brine, dried over sodium sulfate, and evaporated. The crude product was purified by column chromatography on silica gel (elution with 15% and 30% ethyl acetate in hexanes) affording 3.5 g of a solid which was recrystallized from ethyl acetate/hexanes to afford 3.03 g (95.7%) of the title compound. after which time it was cooled to -50° to warm to -35° over 40 min The reaction was quenched by the addition of aqueous ammonium chloride this mixture was poured onto water extracted twice with ethyl acetate The combined extracts were washed with brine dried over sodium sulfate evaporated The crude product was purified by column chromatography on silica gel (elution with 15% and 30% ethyl acetate in hexanes)

Conditions: temp:-60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of carbon tetrabromide (241.6 g, 0.73 mol) in anhydrous DCM (1000 mL) was cooled to −20° C. under nitrogen and triphenylphosphine (191.1 g, 0.73 mol) in anhydrous DCM (1000 mL) was added drop wise. After twenty minutes of stirring, the reaction was cooled to −60° C., and then a mixture of furfural (30 mL, 0.36 mol) and triethylamine (50.5 mL, 0.36 mol) in anhydrous DCM (375 mL) were added drop wise. The mixture was brought to room temperature and diethyl ether (500 mL) was added with stirring. The reaction was filtered and filtrate was concentrated in vacuo. Column chromatography (SiO2, heptanes) yielded the title compound (58.1 g, 63%) as a brown oil: were added drop wise was brought to room temperature with stirring The reaction was filtered filtrate was concentrated in vacuo

Conditions: temp:-60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of carbon tetrabromide (241.6 g, 0.73 mol) in anhydrous DCM (1000 mL) was cooled to −20° C. under nitrogen and triphenylphosphine (191.1 g, 0.73 mol) in anhydrous DCM (1000 mL) was added drop wise. After twenty minutes of stirring, the reaction was cooled to −60° C., and then a mixture of furfural (30 mL, 0.36 mol) and triethylamine (50.5 mL, 0.36 mol) in anhydrous DCM (375 mL) were added drop wise. The mixture was brought to room temperature and diethyl ether (500 mL) was added with stirring. The reaction was filtered and filtrate was concentrated in vacuo. Column chromatography (SiO2, heptanes) yielded the title compound (58.1 g, 63%) as a brown oil: were added drop wise was brought to room temperature with stirring The reaction was filtered filtrate was concentrated in vacuo

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 5.9 g (25 mmoles) of 1,1-dibromo-2-(furan-2-yl)ethylene in 124 mL of anhydrous THF at −20° was added dropwise 31.0 mL of 1.6 M n-butyllithium in hexanes (50 mmoles). This solution was allowed to warm to ambient temperature over a period of 30 min, after which time it was cooled to −50°. 4,6-Dichloro-4-(trifluoromethyl)-2H-3,1-benzoxazin-2-one (2.65 g, 9.27 mmoles) was added in one portion, and the resulting solution was allowed to warm to −35° over 40 min. The reaction was quenched by the addition of aqueous ammonium chloride, and this mixture was poured onto water and extracted twice with ethyl acetate. The combined extracts were washed with brine, dried over sodium sulfate, and evaporated. The crude product was purified by column chromatography on silica gel (elution with 15% and 30% ethyl acetate in hexanes) affording 3.5 g of a solid which was recrystallized from ethyl acetate/hexanes to afford 3.03 g (95.7%) of the title compound. after which time it was cooled to −50° to warm to −35° over 40 min The reaction was quenched by the addition of aqueous ammonium chloride this mixture was poured onto water extracted twice with ethyl acetate The combined extracts were washed with brine dried over sodium sulfate evaporated The crude product was purified by column chromatography on silica gel (elution with 15% and 30% ethyl acetate in hexanes)

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of 5.9 g (25 mmoles) of 1,1-dibromo-2-(furan-2-yl)ethylene in 124 mL of anhydrous THF at -20° was added dropwise 31.0 mL of 1.6 M n-butyllithium in hexanes (50 mmoles). This solution was allowed to warm to ambient temperature over a period of 30 min, after which time it was cooled to -50°. 4,6-Dichloro-4-(trifluoromethyl)-2H-3,1-benzoxazin-2-one (2.65 g, 9.27 mmoles) was added in one portion, and the resulting solution was allowed to warm to -35° over 40 min. The reaction was quenched by the addition of aqueous ammonium chloride, and this mixture was poured onto water and extracted twice with ethyl acetate. The combined extracts were washed with brine, dried over sodium sulfate, and evaporated. The crude product was purified by column chromatography on silica gel (elution with 15% and 30% ethyl acetate in hexanes) affording 3.5 g of a solid which was recrystallized from ethyl acetate/hexanes to afford 3.03 g (95.7%) of the title compound. after which time it was cooled to -50° to warm to -35° over 40 min The reaction was quenched by the addition of aqueous ammonium chloride this mixture was poured onto water extracted twice with ethyl acetate The combined extracts were washed with brine dried over sodium sulfate evaporated The crude product was purified by column chromatography on silica gel (elution with 15% and 30% ethyl acetate in hexanes)