ethyl 2-fluoro-2-methylpropanoate

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:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Into a 50-ml autoclave having a teflon-made internal cylinder were placed 9 ml of a hydrogen fluoride/pyridine mixture [hydrogen fluoride/pyridne =70/30 (wt/wt), containing about 300 mM of hydrogen fluoride] and 9.15 g (91.5 mM) of fluorosulfuric acid. The autoclave contents were cooled to 0° C. Thereto was added 4.0 g (30.5 mM) of ethyl 2-hydroxyisobutyrate. The resulting mixture was subjected to a reaction at 40° C. for 4 hours. After the completion of the reaction, the reaction mixture was poured into ice water. The resulting mixture was extracted with methylene chloride. The extract was dried over anhydrous sodium sulfate and subjected to vacuum distillation to remove methylene chloride. The resulting residue was subjected to distillation to obtain 2.1 g (yield: 52%) of ethyl 2-fluoroisobutyrate having a boiling point of 124°-126° C. The resulting mixture was subjected to a reaction at 40° C. for 4 hours After the completion of the reaction The resulting mixture was extracted with methylene chloride The extract was dried over anhydrous sodium sulfate subjected to vacuum distillation to remove methylene chloride The resulting residue was subjected to distillation

Conditions: temp:-70.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl 2-hydroxyisobutyrate (12.43 g) was stirred in dry methylene chloride (65 ml) at -70° C. under nitrogen. Diethylaminosulphur trifluoride (30.32 g) in dry methylene chloride (5 ml) was added slowly, maintaining the temperature at -70° C. After completion of the addition, the mixture was stirred at -70° C. for 1 hour and was then allowed to warm to room temperature, stood for 3 hours and then overnight. The reaction was then carefully added to ice with vigorous stirring, and the resultant methylene chloride layer combined with a further methylene chloride extract of the aqueous layer. The total organic fraction was washed with brine, dried over magnesium sulphate and the solvent carefully distilled, to leave ethyl 2-fluoro-isobutyrate as a bronze liquid (12.8 g); 1H NMR analysis indicated that this material was >95% pure, and contained 2-3% of ethyl methacrylate. NMR (CDCl3, 270 MHz) δ 1.31(3H,t), 1.58(6H,d), 4.25(2H,q) ppm; 1H NMR (CDCl3, 254 MHz, 19F) δ -148.0 (1F, septet) ppm. After completion of the addition to warm to room temperature stood for 3 hours overnight The reaction was then carefully added to ice with vigorous stirring extract of the aqueous layer The total organic fraction was washed with brine dried over magnesium sulphate the solvent carefully distilled