3,3-difluorocyclobutane-1-carbonyl chloride

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: In a 3-neck flask at −30° C. containing ethyl 4-iodobenzoate (600 mg, 2.17 mmol) in anhydrous tetrahydrofuran (6.00 mL) was added isopropylmagnesium chloride lithium chloride complex (1.84 mL, 2.39 mmol) dropwise and then stirred at the same temperature for another 40 min. Copper iodide (124 mg, 0.650 mmol) was then added quickly in one portion. The mixture was brought to −15° C. for 20 min. to ensure the solid has dissolved. The reaction is then brought back to −40° C. Crude 3,3-difluorocyclobutanecarbonyl chloride (470 mg, 1.50 mmol pure) was then added and the reaction was then warmed to 0° C. over 1 h and then stirred at room temperature for 18 h. The mixture was then diluted with 1 N HCl and extracted three times with ethyl acetate. The combined organic layers were then washed with brine and then dried over sodium sulfate, filtered, and concentrated to provide 680 mg of crude oil. Purification by silica gel flash chromatography (0-10% ethyl acetate in heptane) afforded impure ethyl 4-(3,3-difluorocyclobutanecarbonyl)benzoate (130 mg, approximately 0.24 mmol pure) as a solid. 1H NMR (400 MHz, CDCl3) δ 8.09 (d, J=9.0 Hz, 2H), 7.18 (d, J=9.2 Hz, 2H), 4.39 (q, J=7.4 Hz, 2H), 3.34-3.15 (m, 1H), 3.12-2.78 (m, 4H), 1.40 (t, J=7.4 Hz, 3H). was added isopropylmagnesium chloride lithium chloride complex (1.84 mL, 2.39 mmol) dropwise The mixture was brought to −15° C. for 20 min. has dissolved is then brought back to −40° C stirred at room temperature for 18 h extracted three times with ethyl acetate The combined organic layers were then washed with brine dried over sodium sulfate filtered concentrated to provide 680 mg of crude oil Purification by silica gel flash chromatography (0-10% ethyl acetate in heptane)

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

Procedure: 3,3-Difluorocyclobutanecarboxylic acid (Parkway Scientific, New York, N.Y., USA) (531 mg, 3.90 mmol) was dissolved in dichloromethane (3.00 mL) and oxalyl chloride (1.02 mL, 11.7 mmol) was added. The solution was stirred at room temperature for 4 h before concentrating in vacuo to provide 3,3-difluorocyclobutanecarbonyl chloride (ca. 50% pure), which was carried on without purification. before concentrating in vacuo

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

Procedure: 3,3-Difluorocyclobutanecarboxylic acid (Parkway Scientific, New York, N.Y., USA) (531 mg, 3.90 mmol) was dissolved in dichloromethane (3.00 mL) and oxalyl chloride (1.02 mL, 11.7 mmol) was added. The solution was stirred at room temperature for 4 h before concentrating in vacuo to provide 3,3-difluorocyclobutanecarbonyl chloride (ca. 50% pure), which was carried on without purification. before concentrating in vacuo

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: In a 3-neck flask at −30° C. containing ethyl 4-iodobenzoate (600 mg, 2.17 mmol) in anhydrous tetrahydrofuran (6.00 mL) was added isopropylmagnesium chloride lithium chloride complex (1.84 mL, 2.39 mmol) dropwise and then stirred at the same temperature for another 40 min. Copper iodide (124 mg, 0.650 mmol) was then added quickly in one portion. The mixture was brought to −15° C. for 20 min. to ensure the solid has dissolved. The reaction is then brought back to −40° C. Crude 3,3-difluorocyclobutanecarbonyl chloride (470 mg, 1.50 mmol pure) was then added and the reaction was then warmed to 0° C. over 1 h and then stirred at room temperature for 18 h. The mixture was then diluted with 1 N HCl and extracted three times with ethyl acetate. The combined organic layers were then washed with brine and then dried over sodium sulfate, filtered, and concentrated to provide 680 mg of crude oil. Purification by silica gel flash chromatography (0-10% ethyl acetate in heptane) afforded impure ethyl 4-(3,3-difluorocyclobutanecarbonyl)benzoate (130 mg, approximately 0.24 mmol pure) as a solid. 1H NMR (400 MHz, CDCl3) δ 8.09 (d, J=9.0 Hz, 2H), 7.18 (d, J=9.2 Hz, 2H), 4.39 (q, J=7.4 Hz, 2H), 3.34-3.15 (m, 1H), 3.12-2.78 (m, 4H), 1.40 (t, J=7.4 Hz, 3H). was added isopropylmagnesium chloride lithium chloride complex (1.84 mL, 2.39 mmol) dropwise The mixture was brought to −15° C. for 20 min. has dissolved is then brought back to −40° C stirred at room temperature for 18 h extracted three times with ethyl acetate The combined organic layers were then washed with brine dried over sodium sulfate filtered concentrated to provide 680 mg of crude oil Purification by silica gel flash chromatography (0-10% ethyl acetate in heptane)

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

Procedure: 3,3-Difluorocyclobutanecarboxylic acid (Parkway Scientific, New York, N.Y., USA) (531 mg, 3.90 mmol) was dissolved in dichloromethane (3.00 mL) and oxalyl chloride (1.02 mL, 11.7 mmol) was added. The solution was stirred at room temperature for 4 h before concentrating in vacuo to provide 3,3-difluorocyclobutanecarbonyl chloride (ca. 50% pure), which was carried on without purification. before concentrating in vacuo

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

Procedure: In a 3-neck flask at −30° C. containing ethyl 4-iodobenzoate (600 mg, 2.17 mmol) in anhydrous tetrahydrofuran (6.00 mL) was added isopropylmagnesium chloride lithium chloride complex (1.84 mL, 2.39 mmol) dropwise and then stirred at the same temperature for another 40 min. Copper iodide (124 mg, 0.650 mmol) was then added quickly in one portion. The mixture was brought to −15° C. for 20 min. to ensure the solid has dissolved. The reaction is then brought back to −40° C. Crude 3,3-difluorocyclobutanecarbonyl chloride (470 mg, 1.50 mmol pure) was then added and the reaction was then warmed to 0° C. over 1 h and then stirred at room temperature for 18 h. The mixture was then diluted with 1 N HCl and extracted three times with ethyl acetate. The combined organic layers were then washed with brine and then dried over sodium sulfate, filtered, and concentrated to provide 680 mg of crude oil. Purification by silica gel flash chromatography (0-10% ethyl acetate in heptane) afforded impure ethyl 4-(3,3-difluorocyclobutanecarbonyl)benzoate (130 mg, approximately 0.24 mmol pure) as a solid. 1H NMR (400 MHz, CDCl3) δ 8.09 (d, J=9.0 Hz, 2H), 7.18 (d, J=9.2 Hz, 2H), 4.39 (q, J=7.4 Hz, 2H), 3.34-3.15 (m, 1H), 3.12-2.78 (m, 4H), 1.40 (t, J=7.4 Hz, 3H). was added isopropylmagnesium chloride lithium chloride complex (1.84 mL, 2.39 mmol) dropwise The mixture was brought to −15° C. for 20 min. has dissolved is then brought back to −40° C stirred at room temperature for 18 h extracted three times with ethyl acetate The combined organic layers were then washed with brine dried over sodium sulfate filtered concentrated to provide 680 mg of crude oil Purification by silica gel flash chromatography (0-10% ethyl acetate in heptane)

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

Procedure: 3,3-Difluorocyclobutanecarboxylic acid (Parkway Scientific, New York, N.Y., USA) (531 mg, 3.90 mmol) was dissolved in dichloromethane (3.00 mL) and oxalyl chloride (1.02 mL, 11.7 mmol) was added. The solution was stirred at room temperature for 4 h before concentrating in vacuo to provide 3,3-difluorocyclobutanecarbonyl chloride (ca. 50% pure), which was carried on without purification. before concentrating in vacuo

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

Procedure: In a 3-neck flask at −30° C. containing ethyl 4-iodobenzoate (600 mg, 2.17 mmol) in anhydrous tetrahydrofuran (6.00 mL) was added isopropylmagnesium chloride lithium chloride complex (1.84 mL, 2.39 mmol) dropwise and then stirred at the same temperature for another 40 min. Copper iodide (124 mg, 0.650 mmol) was then added quickly in one portion. The mixture was brought to −15° C. for 20 min. to ensure the solid has dissolved. The reaction is then brought back to −40° C. Crude 3,3-difluorocyclobutanecarbonyl chloride (470 mg, 1.50 mmol pure) was then added and the reaction was then warmed to 0° C. over 1 h and then stirred at room temperature for 18 h. The mixture was then diluted with 1 N HCl and extracted three times with ethyl acetate. The combined organic layers were then washed with brine and then dried over sodium sulfate, filtered, and concentrated to provide 680 mg of crude oil. Purification by silica gel flash chromatography (0-10% ethyl acetate in heptane) afforded impure ethyl 4-(3,3-difluorocyclobutanecarbonyl)benzoate (130 mg, approximately 0.24 mmol pure) as a solid. 1H NMR (400 MHz, CDCl3) δ 8.09 (d, J=9.0 Hz, 2H), 7.18 (d, J=9.2 Hz, 2H), 4.39 (q, J=7.4 Hz, 2H), 3.34-3.15 (m, 1H), 3.12-2.78 (m, 4H), 1.40 (t, J=7.4 Hz, 3H). was added isopropylmagnesium chloride lithium chloride complex (1.84 mL, 2.39 mmol) dropwise The mixture was brought to −15° C. for 20 min. has dissolved is then brought back to −40° C stirred at room temperature for 18 h extracted three times with ethyl acetate The combined organic layers were then washed with brine dried over sodium sulfate filtered concentrated to provide 680 mg of crude oil Purification by silica gel flash chromatography (0-10% ethyl acetate in heptane)

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

Procedure: 3,3-Difluorocyclobutanecarboxylic acid (Parkway Scientific, New York, N.Y., USA) (531 mg, 3.90 mmol) was dissolved in dichloromethane (3.00 mL) and oxalyl chloride (1.02 mL, 11.7 mmol) was added. The solution was stirred at room temperature for 4 h before concentrating in vacuo to provide 3,3-difluorocyclobutanecarbonyl chloride (ca. 50% pure), which was carried on without purification. before concentrating in vacuo