2,2-dichloro-1,1,1-trifluoroethane

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

Procedure: An alternative approach to HCFC's is the chlorination of fluorocarbons such as CH3CF3 (HFC-143a). For example, McBee (Industrial and Engineering Chemistry, Vol. 39, pp. 409-412 (1947)) reported that vapor phase chlorination of HFC-143a afforded a mixture of HCFC-133a, HCFC-132b, CHCl2CF3 (HCFC-123), and the fully chlorinated CF3CCl3 (CFC-113a). McBee also reported the chlorination of CH3CClF2 (HCFC-142b) to give HCFC-132b, HCFC-122, and the fully chlorinated CClF2CCl3 (CFC-112a). Again, using this technique --CH2Cl and --CHCl2 groups dominate the attainable substitution pattern. afforded

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To an agitated mixture of methyl 3,3-dimethyl-5-oxopentanoate (1.0 g), 1,1-dichloro-2,2,2-trifluoroethane (1.06 g) and dry tetrahydrofuran (10 cm3), maintained at -78° C., was added, over a period of 5 minutes, sodium t-butoxide (1.66 cm3 of a 42% w/w solution in dimethylformamide) after which the mixture continued to be agitated at -78° C. for a further 60 minutes. The reaction was quenched with saturated ammonium chloride at low temperature and the mixture allowed to warm to the ambient temperature. After addition of water (20 cm3) and separation of the organic phase, the aqueous phase was extracted with di-isopropyl ether (3×30 cm3) and the extracts combined with the organic phase, which was washed with brine (2×10 cm3) and dried over anhydrous magnesium sulphate. After removal of the volatile components by evaporation under reduced pressure the residual oil was purified by column chromatography (silica gel column eluted with a 9:1 mixture (by volume) of hexane and ethyl acetate) to give methyl 6,6-dichloro-3,3-dimethyl-5-hydroxy-7,7,7-trifluoroheptanoate as a colourless oil (yield 56%). was added, over a period of 5 minutes The reaction was quenched with saturated ammonium chloride at low temperature to warm to the ambient temperature After addition of water (20 cm3) and separation of the organic phase the aqueous phase was extracted with di-isopropyl ether (3×30 cm3) was washed with brine (2×10 cm3) dried over anhydrous magnesium sulphate After removal of the volatile components by evaporation under reduced pressure the residual oil was purified by column chromatography (silica gel column eluted with a 9:1 mixture (by volume) of hexane and ethyl acetate)

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To an agitated mixture of methyl 3,3-dimethyl-5-oxopentanoate (1.0 g), 1,1-dichloro-2,2,2-trifluoroethane (1.06 g) and dry tetrahydrofuran (10 cm3), maintained at -78° C., was added, over a period of 5 minutes, sodium t-butoxide (1.66 cm3 of a 42% w/w solution in dimethylformamide) after which the mixture continued to be agitated at -78° C. for a further 60 minutes. The reaction was quenched with saturated ammonium chloride at low temperature and the mixture allowed to warm to the ambient temperature. After addition of water (20 cm3) and separation of the organic phase, the aqueous phase was extracted with di-isopropyl ether (3×30 cm3) and the extracts combined with the organic phase, which was washed with brine (2×10 cm3) and dried over anhydrous magnesium sulphate. After removal of the volatile components by evaporation under reduced pressure the residual oil was purified by column chromatography (silica gel column eluted with a 9:1 mixture (by volume) of hexane and ethyl acetate) to give methyl 6,6-dichloro-3,3-dimethyl-5-hydroxy-7,7,7-trifluoroheptanoate as a colourless oil (yield 56%). was added, over a period of 5 minutes The reaction was quenched with saturated ammonium chloride at low temperature to warm to the ambient temperature After addition of water (20 cm3) and separation of the organic phase the aqueous phase was extracted with di-isopropyl ether (3×30 cm3) was washed with brine (2×10 cm3) dried over anhydrous magnesium sulphate After removal of the volatile components by evaporation under reduced pressure the residual oil was purified by column chromatography (silica gel column eluted with a 9:1 mixture (by volume) of hexane and ethyl acetate)