ethyl 2,2-dibromo-2-fluoroacetate

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: Add 8.45 mL (50.4 mmol) of triethylsilyl chloride to a suspension of 2.99 g of activated Zn (45.8 mmol) in anhydrous acetonitrile (100 mL) at −20° C. and stir the mixture for 5 minutes. Add 8.0 mL (57.3 mmol) of ethyl 2,2-dibromo-2-fluoracetate and stir the mixture for 90 minutes at −20° C. Add 1.86 mL (22.9 mmol) of 2-cyclopenten-1-one, and stir the reaction mixture overnight, allowing the temperature to rise slowly to room temperature. Add HCl 1N (125 mL) and EtOAc (100 mL). Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL), dry over anhydrous MgSO4, filter and concentrate under reduced pressure. Purify the residue by column chromatography using EtOAc/hexane (1:8) as eluent to give the title compound (5.36 g, 88% overall yield) as a colorless oil as a mixture of diastereoisomers. stir the mixture for 90 minutes at −20° C stir the reaction mixture overnight to rise slowly to room temperature Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL) dry over anhydrous MgSO4 filter concentrate under reduced pressure Purify the residue by column chromatography

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

Procedure: Add 8.45 mL (50.4 mmol) of triethylsilyl chloride to a suspension of 2.99 g of activated Zn (45.8 mmol) in anhydrous acetonitrile (100 mL) at −20° C. and stir the mixture for 5 minutes. Add 8.0 mL (57.3 mmol) of ethyl 2,2-dibromo-2-fluoracetate and stir the mixture for 90 minutes at −20° C. Add 1.86 mL (22.9 mmol) of 2-cyclopenten-1-one, and stir the reaction mixture overnight, allowing the temperature to rise slowly to room temperature. Add HCl 1N (125 mL) and EtOAc (100 mL). Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL), dry over anhydrous MgSO4, filter and concentrate under reduced pressure. Purify the residue by column chromatography using EtOAc/hexane (1:8) as eluent to give the title compound (5.36 g, 88% overall yield) as a colorless oil as a mixture of diastereoisomers. stir the mixture for 90 minutes at −20° C stir the reaction mixture overnight to rise slowly to room temperature Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL) dry over anhydrous MgSO4 filter concentrate under reduced pressure Purify the residue by column chromatography

Conditions: temp:-20.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Under a nitrogen atmosphere, 40.4 g of ethyl dibromofluoroacetate was added dropwise to a suspension of 22.4 mL of chlorotriethylsilane, 8.0 g of zinc, and 250 mL of acetonitrile, over 2 hours at −20° C. The mixture was further stirred for 1.5 hours at −20° C. 2-cyclopenten-1-one in an amount of 5.0 g was added dropwise to the reaction solution, and the mixture was stirred for 15 hours at −20° C. The reaction was quenched with 1M hydrochloric acid, followed by concentration under reduced pressure. After extraction of the residue with diethyl ether twice, the organic layers were combined. The combined organic layer was washed with a saturated aqueous solution of sodium chloride, and was subsequently dried over anhydrous sodium sulfate. After the desiccant was filtered off, the filtrate was concentrated under reduced pressure. The residue was purified by column chromatography (silica gel: Wako gel C200 (produced by Wako Pure Chemical Industries Ltd.), eluent: hexane-ethyl acetate=10:1 to 8:1), thereby yielding 6.2 g of (2SR)ethyl 2-bromo-2-fluoro-2-[(1RS)-3-oxocyclopentyl]acetate and 4.4 g of (2RS)ethyl 2-bromo-2-fluoro-2-[(1RS)-3-oxocyclopentyl]acetate. the mixture was stirred for 15 hours at −20° C The reaction was quenched with 1M hydrochloric acid followed by concentration under reduced pressure After extraction of the residue with diethyl ether twice The combined organic layer was washed with a saturated aqueous solution of sodium chloride was subsequently dried over anhydrous sodium sulfate After the desiccant was filtered off the filtrate was concentrated under reduced pressure The residue was purified by column chromatography (silica gel: Wako gel C200 (produced by Wako Pure Chemical Industries Ltd.), eluent: hexane-ethyl acetate=10:1 to 8:1)

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

Procedure: Add 8.45 mL (50.4 mmol) of triethylsilyl chloride to a suspension of 2.99 g of activated Zn (45.8 mmol) in anhydrous acetonitrile (100 mL) at −20° C. and stir the mixture for 5 minutes. Add 8.0 mL (57.3 mmol) of ethyl 2,2-dibromo-2-fluoracetate and stir the mixture for 90 minutes at −20° C. Add 1.86 mL (22.9 mmol) of 2-cyclopenten-1-one, and stir the reaction mixture overnight, allowing the temperature to rise slowly to room temperature. Add HCl 1N (125 mL) and EtOAc (100 mL). Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL), dry over anhydrous MgSO4, filter and concentrate under reduced pressure. Purify the residue by column chromatography using EtOAc/hexane (1:8) as eluent to give the title compound (5.36 g, 88% overall yield) as a colorless oil as a mixture of diastereoisomers. stir the mixture for 90 minutes at −20° C stir the reaction mixture overnight to rise slowly to room temperature Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL) dry over anhydrous MgSO4 filter concentrate under reduced pressure Purify the residue by column chromatography

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

Procedure: Add 8.45 mL (50.4 mmol) of triethylsilyl chloride to a suspension of 2.99 g of activated Zn (45.8 mmol) in anhydrous acetonitrile (100 mL) at −20° C. and stir the mixture for 5 minutes. Add 8.0 mL (57.3 mmol) of ethyl 2,2-dibromo-2-fluoracetate and stir the mixture for 90 minutes at −20° C. Add 1.86 mL (22.9 mmol) of 2-cyclopenten-1-one, and stir the reaction mixture overnight, allowing the temperature to rise slowly to room temperature. Add HCl 1N (125 mL) and EtOAc (100 mL). Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL), dry over anhydrous MgSO4, filter and concentrate under reduced pressure. Purify the residue by column chromatography using EtOAc/hexane (1:8) as eluent to give the title compound (5.36 g, 88% overall yield) as a colorless oil as a mixture of diastereoisomers. stir the mixture for 90 minutes at −20° C stir the reaction mixture overnight to rise slowly to room temperature Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL) dry over anhydrous MgSO4 filter concentrate under reduced pressure Purify the residue by column chromatography

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

Procedure: Add 8.45 mL (50.4 mmol) of triethylsilyl chloride to a suspension of 2.99 g of activated Zn (45.8 mmol) in anhydrous acetonitrile (100 mL) at −20° C. and stir the mixture for 5 minutes. Add 8.0 mL (57.3 mmol) of ethyl 2,2-dibromo-2-fluoracetate and stir the mixture for 90 minutes at −20° C. Add 1.86 mL (22.9 mmol) of 2-cyclopenten-1-one, and stir the reaction mixture overnight, allowing the temperature to rise slowly to room temperature. Add HCl 1N (125 mL) and EtOAc (100 mL). Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL), dry over anhydrous MgSO4, filter and concentrate under reduced pressure. Purify the residue by column chromatography using EtOAc/hexane (1:8) as eluent to give the title compound (5.36 g, 88% overall yield) as a colorless oil as a mixture of diastereoisomers. stir the mixture for 90 minutes at −20° C stir the reaction mixture overnight to rise slowly to room temperature Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL) dry over anhydrous MgSO4 filter concentrate under reduced pressure Purify the residue by column chromatography

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

Procedure: Add 8.45 mL (50.4 mmol) of triethylsilyl chloride to a suspension of 2.99 g of activated Zn (45.8 mmol) in anhydrous acetonitrile (100 mL) at −20° C. and stir the mixture for 5 minutes. Add 8.0 mL (57.3 mmol) of ethyl 2,2-dibromo-2-fluoracetate and stir the mixture for 90 minutes at −20° C. Add 1.86 mL (22.9 mmol) of 2-cyclopenten-1-one, and stir the reaction mixture overnight, allowing the temperature to rise slowly to room temperature. Add HCl 1N (125 mL) and EtOAc (100 mL). Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL), dry over anhydrous MgSO4, filter and concentrate under reduced pressure. Purify the residue by column chromatography using EtOAc/hexane (1:8) as eluent to give the title compound (5.36 g, 88% overall yield) as a colorless oil as a mixture of diastereoisomers. stir the mixture for 90 minutes at −20° C stir the reaction mixture overnight to rise slowly to room temperature Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL) dry over anhydrous MgSO4 filter concentrate under reduced pressure Purify the residue by column chromatography

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

Procedure: Add 8.45 mL (50.4 mmol) of triethylsilyl chloride to a suspension of 2.99 g of activated Zn (45.8 mmol) in anhydrous acetonitrile (100 mL) at −20° C. and stir the mixture for 5 minutes. Add 8.0 mL (57.3 mmol) of ethyl 2,2-dibromo-2-fluoracetate and stir the mixture for 90 minutes at −20° C. Add 1.86 mL (22.9 mmol) of 2-cyclopenten-1-one, and stir the reaction mixture overnight, allowing the temperature to rise slowly to room temperature. Add HCl 1N (125 mL) and EtOAc (100 mL). Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL), dry over anhydrous MgSO4, filter and concentrate under reduced pressure. Purify the residue by column chromatography using EtOAc/hexane (1:8) as eluent to give the title compound (5.36 g, 88% overall yield) as a colorless oil as a mixture of diastereoisomers. stir the mixture for 90 minutes at −20° C stir the reaction mixture overnight to rise slowly to room temperature Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL) dry over anhydrous MgSO4 filter concentrate under reduced pressure Purify the residue by column chromatography

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

Procedure: Add 8.45 mL (50.4 mmol) of triethylsilyl chloride to a suspension of 2.99 g of activated Zn (45.8 mmol) in anhydrous acetonitrile (100 mL) at −20° C. and stir the mixture for 5 minutes. Add 8.0 mL (57.3 mmol) of ethyl 2,2-dibromo-2-fluoracetate and stir the mixture for 90 minutes at −20° C. Add 1.86 mL (22.9 mmol) of 2-cyclopenten-1-one, and stir the reaction mixture overnight, allowing the temperature to rise slowly to room temperature. Add HCl 1N (125 mL) and EtOAc (100 mL). Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL), dry over anhydrous MgSO4, filter and concentrate under reduced pressure. Purify the residue by column chromatography using EtOAc/hexane (1:8) as eluent to give the title compound (5.36 g, 88% overall yield) as a colorless oil as a mixture of diastereoisomers. stir the mixture for 90 minutes at −20° C stir the reaction mixture overnight to rise slowly to room temperature Wash the organic layer with saturated NaHCO3 (2×150 mL), water (2×150 mL) and brine (2×150 mL) dry over anhydrous MgSO4 filter concentrate under reduced pressure Purify the residue by column chromatography