2-bromo-1,1,3,3,3-pentafluoroprop-1-ene

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

Procedure: In a quartz photochemical reaction vessel equipped with a dry ice condenser, a stirred mixture of methanol (20 g), ditert-butyl peroxide (0.79) and CF3C(Br)═CF2 (10 g, 0.05 mol), was irradiated at 254 nm for ˜6 hr at ambient temperature for under nitrogen. (Note: CF3CBr═CF2 was added as a liquid (BP, 24-25° C.) in one lot before the reaction). Then the reaction mixture was concentrated to remove excess methanol. The concentrated material was taken in ˜40 mL ether, washed with 20 ml 20% aqueous sodium bisulphite followed by brine (10 mL) and distilled to afford the CF3CHBrCF2CH2OH (2.0 g) as a colorless liquid. Yield=26% based on CF3CBr═CF2. Boiling point, 30-31° C./ 8-10 mm Hg. GC-MS: m/e at (C4H4BrF5O) for M+; NMR spectra are consistent with the structure. In a quartz photochemical reaction vessel equipped with a dry ice condenser was irradiated at 254 nm for ˜6 hr at ambient temperature for under nitrogen Then the reaction mixture was concentrated to remove excess methanol washed with 20 ml 20% aqueous sodium bisulphite distilled

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

Procedure: To a 250 mL 3-necked round bottom flask operating under nitrogen purge, equipped with a water condenser (at about 15-20° C.), stirrer, and fitted with a dry ice trap (at about −78° C.), was added 100 mL aqueous potassium hydroxide (23 wt. %) solution and the crown ether, 18-crown-6, (0.1 g, 0.37 mmol) To this solution at about 20° C., was added CF3CHBrCF2Br (24.6 g, 84 mmol) drop-wise via an addition funnel over a period of about 35 minutes. The dehydrobrominated product, CF3CBr═CF2 (gas chromatograph retention time, 2.0 min), as formed, was continuously collected in the dry ice trap. After complete addition of CF3CHBrCF2Br, the reaction mixture was stirred for an additional 60 minutes. A total of 17.1 g (81 mmol) of CF3CBr═CF2 (96% yield), was collected in the dry ice trap. The structure was confirmed by NMR spectroscopy. To a 250 mL 3-necked round bottom flask operating under nitrogen purge equipped with a water condenser (at about 15-20° C.), stirrer fitted with a dry ice trap (at about −78° C.) was added 100 mL aqueous potassium hydroxide (23 wt. %) solution