3-fluorooxolan-2-one

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

Procedure: Hydrogen bromide gas was added over a period of about 30 minutes to a solution of 2-fluorobutyrolactone (1.8 g) in ethanol (15 ml) at 0° C. The reaction mixture was left at room temperature for 3 days, after which it was evaporated in vacuo. The residue was dissolved in icewater, the solution was neutralized with sodiumcarbonate and extracted with ether. The ether solution was washed with an aqueous saturated Na2SO4 solution, dried over Na2SO4 and evaporated to give 4-bromo-2-fluorobutyric acid ethyl ester (1.26 g, 34%). nD20 =1.4698. 1H-NMR (CDCl3, MeSi)δ: 1.3 (t, J=7 Hz, CH3); 2.1-2.8 (m, CH2); 3.55 (t, J=7 Hz, CH2Br); 4.3 (q, J=7 Hz, CH2); 4.75 and 5.55 (two triplets, J=6 Hz, CHF, JCHF =50 Hz). after which it was evaporated in vacuo The residue was dissolved in icewater extracted with ether The ether solution was washed with an aqueous saturated Na2SO4 solution dried over Na2SO4 evaporated

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

Procedure: Hydrogen bromide gas was added over a period of about 30 minutes to a solution of 2-fluorobutyrolactone (1.8 g) in ethanol (15 ml) at 0° C. The reaction mixture was left at room temperature for 3 days, after which it was evaporated in vacuo. The residue was dissolved in icewater, the solution was neutralized with sodiumcarbonate and extracted with ether. The ether solution was washed with an aqueous saturated Na2SO4 solution, dried over Na2SO4 and evaporated to give 4-bromo-2-fluorobutyric acid ethyl ester (1.26 g, 34%). nD20 =1.4698. 1H-NMR (CDCl3, MeSi)δ: 1.3 (t, J=7 Hz, CH3); 2.1-2.8 (m, CH2); 3.55 (t, J=7 Hz, CH2Br); 4.3 (q, J=7 Hz, CH2); 4.75 and 5.55 (two triplets, J=6 Hz, CHF, JCHF =50 Hz). after which it was evaporated in vacuo The residue was dissolved in icewater extracted with ether The ether solution was washed with an aqueous saturated Na2SO4 solution dried over Na2SO4 evaporated

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

Procedure: Hydrogen bromide gas was added over a period of about 30 minutes to a solution of 2-fluorobutyrolactone (1.8 g) in ethanol (15 ml) at 0° C. The reaction mixture was left at room temperature for 3 days, after which it was evaporated in vacuo. The residue was dissolved in icewater, the solution was neutralized with sodiumcarbonate and extracted with ether. The ether solution was washed with an aqueous saturated Na2SO4 solution, dried over Na2SO4 and evaporated to give 4-bromo-2-fluorobutyric acid ethyl ester (1.26 g, 34%). nD20 =1.4698. 1H-NMR (CDCl3, MeSi)δ: 1.3 (t, J=7 Hz, CH3); 2.1-2.8 (m, CH2); 3.55 (t, J=7 Hz, CH2Br); 4.3 (q, J=7 Hz, CH2); 4.75 and 5.55 (two triplets, J=6 Hz, CHF, JCHF =50 Hz). after which it was evaporated in vacuo The residue was dissolved in icewater extracted with ether The ether solution was washed with an aqueous saturated Na2SO4 solution dried over Na2SO4 evaporated