5-prop-2-enylcyclopent-2-en-1-one

Conditions: temp:60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A stirred solution of 5-(propene-3-yl)cyclopent-2-enone (0.428, 3.5 mmol) in nitromethane (2 mL) under nitrogen was treated with DOWEX® 550A-OH resin (0.80 g, rinsed with methanol and partially air dried), and heated to 60° C. for 2 h. The mixture was cooled to room temperature, diluted with dichloromethane (20 mL), and filtered. The filtrate was concentrated in vacuo, redissolved in minimum dichloromethane, and added to a silica gel column (˜100 cc) and eluted with dichloromethane to afford the subject compound (0.368 g, 57%) as a colorless oil. NMR (CDCl3): δ 5.65-5.80 (m, 1 H), 5.00-5.15 (m, 2 H), 4.40-4.50 (m, 2 H), 2.85-3.15 (m, 1 H), 2.30-2.70 (m, 4 H), 1.90-2.20 (m, 3 H). MS (M+1): 183.9. rinsed with methanol and partially air dried), and The mixture was cooled to room temperature diluted with dichloromethane (20 mL) filtered The filtrate was concentrated in vacuo redissolved in minimum dichloromethane added to a silica gel column (˜100 cc) eluted with dichloromethane

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

Procedure: A solution of 5-(propene-3-yl)cyclopent-2-enone (4.28 g, 35 mmol) in dichloromethane (15 mL) was treated with benzyl carbamate (10.6 g, 70 mmol) and bismuth trinitrate pentahydrate (2.2 g, 4.5 mmol), stirred rapidly for 18 h, then diluted with dichloromethane (50 mL). The mixture was filtered through Celite® (rinse with dichloromethane) and the filtrate added directly to a silica gel column (˜550 cc). Elution first with 3:2 petroleum ether/dichloromethane afforded recovered starting material (1.01 g), then 4:1 heptane/ethyl acetate gave the subject compound (4.54 g, 47.5% uncorrected yield) as a pale yellow oil. NMR (CDCl3): δ 7.28 (br s, 5 H), 5.55-5.70 (m, 1 H), 5.03 (br s, 2 H), 4.90-5.10 (m, 2 H), 4.75-4.90 (m, 1 H), 4.10-4.30 (m, 1 H), 2.40-2.80 (m, 2 H), 2.15-2.40 (m, 2 H), 1.85-2.15 (m, 3 H). MS (M+Na): 296.0; MS (M−H2O+1): 256.0 (no M+1 visible). The mixture was filtered through Celite® (rinse with dichloromethane) the filtrate added directly to a silica gel column (˜550 cc) Elution first with 3:2 petroleum ether/dichloromethane afforded recovered 4:1 heptane/ethyl acetate gave the subject compound (4.54 g, 47.5% uncorrected yield) as a pale yellow oil

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

Procedure: A solution of 5-(propene-3-yl)cyclopent-2-enone (4.28 g, 35 mmol) in dichloromethane (15 mL) was treated with benzyl carbamate (10.6 g, 70 mmol) and bismuth trinitrate pentahydrate (2.2 g, 4.5 mmol), stirred rapidly for 18 h, then diluted with dichloromethane (50 mL). The mixture was filtered through Celite® (rinse with dichloromethane) and the filtrate added directly to a silica gel column (˜550 cc). Elution first with 3:2 petroleum ether/dichloromethane afforded recovered starting material (1.01 g), then 4:1 heptane/ethyl acetate gave the subject compound (4.54 g, 47.5% uncorrected yield) as a pale yellow oil. NMR (CDCl3): δ 7.28 (br s, 5 H), 5.55-5.70 (m, 1 H), 5.03 (br s, 2 H), 4.90-5.10 (m, 2 H), 4.75-4.90 (m, 1 H), 4.10-4.30 (m, 1 H), 2.40-2.80 (m, 2 H), 2.15-2.40 (m, 2 H), 1.85-2.15 (m, 3 H). MS (M+Na): 296.0; MS (M−H2O+1): 256.0 (no M+1 visible). The mixture was filtered through Celite® (rinse with dichloromethane) the filtrate added directly to a silica gel column (˜550 cc) Elution first with 3:2 petroleum ether/dichloromethane afforded recovered 4:1 heptane/ethyl acetate gave the subject compound (4.54 g, 47.5% uncorrected yield) as a pale yellow oil

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

Procedure: A stirred solution of 5-allylcyclopent-2-enone (2.20 g, 18 mmol), t-butyl carbamate (4.70 g, 40 mmol), and tetra-n-butylammonium bromide (6.45 g, 20 mmol) in anhydrous dichloromethane (40 mL) under nitrogen was cooled in an ice bath (3° C.) and treated dropwise with boron trifluoride etherate (2.22 mL, 18 mmol). The reaction mixture was allowed to warm to room temperature and stirred for 18 h. Saturated aqueous sodium bicarbonate (40 mL) was added and then mixture stirred for 15 min and separated. The aqueous solution was extracted with dichloromethane (2×20 mL) and the combined organic solution was washed with water and saturated aqueous sodium chloride (20 mL each), dried (Na2SO4), and concentrated in vacuo. The residue was dissolved in minimum dichloromethane and added to a column of silica gel (˜300 cc) and eluted first with 85:15 heptane/ethyl acetate to afford recovered starting material (0.35 g), then with 4:1 heptane/ethyl acetate to afford a mixture of t-butyl carbamate and subject compound. This mixture was warmed in heptane and filtered to remove most of the t-butyl carbamate, then the filtrate was added to a column of silica gel (˜300 cc) and eluted with 6:3:1 heptane/dichloromethane/ethyl acetate to afford tert-butyl 3-allyl-4-oxocyclopentylcarbamate 1.17 g (27%) as a pale amber solid. NMR (CDCl3): δ 5.60-5.75 (m, 1 H), 4.90-5.05 (m, 2 H), 4.50 (br s, 1 H), 4.00-4.25 (m, 1 H), 2.30-2.80 (m, 3 H), 2.20-2.30 (m, 1 H), 1.85-2.15 (m, 3 H), 1.38 (s, 9 H). MS (M+1): 240.1. mixture stirred for 15 min separated The aqueous solution was extracted with dichloromethane (2×20 mL) the combined organic solution was washed with water and saturated aqueous sodium chloride (20 mL each) dried (Na2SO4) concentrated in vacuo The residue was dissolved in minimum dichloromethane added to a column of silica gel (˜300 cc) eluted first with 85:15 heptane/ethyl acetate to afford recovered with 4:1 heptane/ethyl acetate to afford filtered to remove most of the t-butyl carbamate the filtrate was added to a column of silica gel (˜300 cc) eluted with 6:3:1 heptane/dichloromethane/ethyl acetate

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

Procedure: A stirred solution of 5-allylcyclopent-2-enone (2.20 g, 18 mmol), t-butyl carbamate (4.70 g, 40 mmol), and tetra-n-butylammonium bromide (6.45 g, 20 mmol) in anhydrous dichloromethane (40 mL) under nitrogen was cooled in an ice bath (3° C.) and treated dropwise with boron trifluoride etherate (2.22 mL, 18 mmol). The reaction mixture was allowed to warm to room temperature and stirred for 18 h. Saturated aqueous sodium bicarbonate (40 mL) was added and then mixture stirred for 15 min and separated. The aqueous solution was extracted with dichloromethane (2×20 mL) and the combined organic solution was washed with water and saturated aqueous sodium chloride (20 mL each), dried (Na2SO4), and concentrated in vacuo. The residue was dissolved in minimum dichloromethane and added to a column of silica gel (˜300 cc) and eluted first with 85:15 heptane/ethyl acetate to afford recovered starting material (0.35 g), then with 4:1 heptane/ethyl acetate to afford a mixture of t-butyl carbamate and subject compound. This mixture was warmed in heptane and filtered to remove most of the t-butyl carbamate, then the filtrate was added to a column of silica gel (˜300 cc) and eluted with 6:3:1 heptane/dichloromethane/ethyl acetate to afford tert-butyl 3-allyl-4-oxocyclopentylcarbamate 1.17 g (27%) as a pale amber solid. NMR (CDCl3): δ 5.60-5.75 (m, 1 H), 4.90-5.05 (m, 2 H), 4.50 (br s, 1 H), 4.00-4.25 (m, 1 H), 2.30-2.80 (m, 3 H), 2.20-2.30 (m, 1 H), 1.85-2.15 (m, 3 H), 1.38 (s, 9 H). MS (M+1): 240.1. mixture stirred for 15 min separated The aqueous solution was extracted with dichloromethane (2×20 mL) the combined organic solution was washed with water and saturated aqueous sodium chloride (20 mL each) dried (Na2SO4) concentrated in vacuo The residue was dissolved in minimum dichloromethane added to a column of silica gel (˜300 cc) eluted first with 85:15 heptane/ethyl acetate to afford recovered with 4:1 heptane/ethyl acetate to afford filtered to remove most of the t-butyl carbamate the filtrate was added to a column of silica gel (˜300 cc) eluted with 6:3:1 heptane/dichloromethane/ethyl acetate

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

Procedure: A stirred, ice cold (3° C.) solution of 2-allyl-5-(phenylselanyl)cyclopentanone, mixture of isomers (12.0 g, 43 mmol) in dichloromethane (200 mL) in a 1 L round bottomed-flask equipped for boil-over containment was treated with saturated aqueous ammonium chloride (45 mL), then dropwise with 30% aqueous hydrogen peroxide (22 mL), and slowly carefully warmed to room temperature. At approximately 20° C. a vigorous exotherm started, and the ice bath was re-applied. The mixture was cooled to room temperature and stirred for 1 h, then the solution was washed with water (100 mL), stirred with 10% aqueous sodium thiosulfate pentahydrate (75 mL) for 10 min, and separated. The organic solution was washed with saturated aqueous sodium bicarbonate and saturated aqueous sodium chloride (75 mL each), dried (Na2SO4), and concentrated to 30 mL volume. The solution was added to a silica gel column (˜400 cc) and eluted with dichloromethane to afford (after very gentle concentration of appropriate fractions) 5-allylcyclopent-2-enone (3.95 g, 75%) as a very pale yellow oil. NMR (CDCl3): δ 7.61 (m, 1 H), 6.12 (m, 1 H), 5.60-5.75 (m, 1 H), 4.90-5.05 (m, 2 H), 2.70-2.80 (m, 1H), 2.45-2.55 (m, 1 H), 2.30-2.40 (m, 2 H), 2.05-2.15 (m, 1 H). equipped for boil-over containment At approximately 20° C. the solution was washed with water (100 mL) stirred with 10% aqueous sodium thiosulfate pentahydrate (75 mL) for 10 min separated The organic solution was washed with saturated aqueous sodium bicarbonate and saturated aqueous sodium chloride (75 mL each) dried (Na2SO4) concentrated to 30 mL volume The solution was added to a silica gel column (˜400 cc) eluted with dichloromethane to afford ( after very gentle concentration of appropriate fractions) 5-allylcyclopent-2-enone (3.95 g, 75%) as a very pale yellow oil

Conditions: temp:60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A stirred solution of 5-(propene-3-yl)cyclopent-2-enone (0.428, 3.5 mmol) in nitromethane (2 mL) under nitrogen was treated with DOWEX® 550A-OH resin (0.80 g, rinsed with methanol and partially air dried), and heated to 60° C. for 2 h. The mixture was cooled to room temperature, diluted with dichloromethane (20 mL), and filtered. The filtrate was concentrated in vacuo, redissolved in minimum dichloromethane, and added to a silica gel column (˜100 cc) and eluted with dichloromethane to afford the subject compound (0.368 g, 57%) as a colorless oil. NMR (CDCl3): δ 5.65-5.80 (m, 1 H), 5.00-5.15 (m, 2 H), 4.40-4.50 (m, 2 H), 2.85-3.15 (m, 1 H), 2.30-2.70 (m, 4 H), 1.90-2.20 (m, 3 H). MS (M+1): 183.9. rinsed with methanol and partially air dried), and The mixture was cooled to room temperature diluted with dichloromethane (20 mL) filtered The filtrate was concentrated in vacuo redissolved in minimum dichloromethane added to a silica gel column (˜100 cc) eluted with dichloromethane

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

Procedure: A solution of 5-(propene-3-yl)cyclopent-2-enone (4.28 g, 35 mmol) in dichloromethane (15 mL) was treated with benzyl carbamate (10.6 g, 70 mmol) and bismuth trinitrate pentahydrate (2.2 g, 4.5 mmol), stirred rapidly for 18 h, then diluted with dichloromethane (50 mL). The mixture was filtered through Celite® (rinse with dichloromethane) and the filtrate added directly to a silica gel column (˜550 cc). Elution first with 3:2 petroleum ether/dichloromethane afforded recovered starting material (1.01 g), then 4:1 heptane/ethyl acetate gave the subject compound (4.54 g, 47.5% uncorrected yield) as a pale yellow oil. NMR (CDCl3): δ 7.28 (br s, 5 H), 5.55-5.70 (m, 1 H), 5.03 (br s, 2 H), 4.90-5.10 (m, 2 H), 4.75-4.90 (m, 1 H), 4.10-4.30 (m, 1 H), 2.40-2.80 (m, 2 H), 2.15-2.40 (m, 2 H), 1.85-2.15 (m, 3 H). MS (M+Na): 296.0; MS (M−H2O+1): 256.0 (no M+1 visible). The mixture was filtered through Celite® (rinse with dichloromethane) the filtrate added directly to a silica gel column (˜550 cc) Elution first with 3:2 petroleum ether/dichloromethane afforded recovered 4:1 heptane/ethyl acetate gave the subject compound (4.54 g, 47.5% uncorrected yield) as a pale yellow oil

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

Procedure: A stirred solution of 5-allylcyclopent-2-enone (2.20 g, 18 mmol), t-butyl carbamate (4.70 g, 40 mmol), and tetra-n-butylammonium bromide (6.45 g, 20 mmol) in anhydrous dichloromethane (40 mL) under nitrogen was cooled in an ice bath (3° C.) and treated dropwise with boron trifluoride etherate (2.22 mL, 18 mmol). The reaction mixture was allowed to warm to room temperature and stirred for 18 h. Saturated aqueous sodium bicarbonate (40 mL) was added and then mixture stirred for 15 min and separated. The aqueous solution was extracted with dichloromethane (2×20 mL) and the combined organic solution was washed with water and saturated aqueous sodium chloride (20 mL each), dried (Na2SO4), and concentrated in vacuo. The residue was dissolved in minimum dichloromethane and added to a column of silica gel (˜300 cc) and eluted first with 85:15 heptane/ethyl acetate to afford recovered starting material (0.3 5 g), then with 4:1 heptane/ethyl acetate to afford a mixture of t-butyl carbamate and subject compound. This mixture was warmed in heptane and filtered to remove most of the t-butyl carbamate, then the filtrate was added to a column of silica gel (˜300 cc) and eluted with 6:3:1 heptane/dichloromethane/ethyl acetate to afford tert-butyl 3-allyl-4-oxocyclopentylcarbamate 1.17 g (27%) as a pale amber solid. NMR (CDCl3): δ 5.60-5.75 (m, 1 H), 4.90-5.05 (m, 2 H), 4.50 (br s, 1 H), 4.00-4.25 (m, 1 H), 2.30-2.80 (m, 3 H), 2.20-2.30 (m, 1 H), 1.85-2.15 (m, 3 H), 1.38 (s, 9 H). MS (M+1): 240.1. mixture stirred for 15 min separated The aqueous solution was extracted with dichloromethane (2×20 mL) the combined organic solution was washed with water and saturated aqueous sodium chloride (20 mL each) dried (Na2SO4) concentrated in vacuo The residue was dissolved in minimum dichloromethane added to a column of silica gel (˜300 cc) eluted first with 85:15 heptane/ethyl acetate to afford recovered with 4:1 heptane/ethyl acetate to afford filtered to remove most of the t-butyl carbamate the filtrate was added to a column of silica gel (˜300 cc) eluted with 6:3:1 heptane/dichloromethane/ethyl acetate

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

Procedure: A stirred ice cold (3° C.) solution of 2-allyl-5-(phenylselanyl)cyclopentanone, mixture if isomers (12.0 g, 43 mmol) in dichloromethane (200 mL) in a 1 L round bottomed-flask equipped for boil-over containment was treated with saturated aqueous ammonium chloride (45 mL), then dropwise with 30% aqueous hydrogen peroxide (22 mL), and slowly carefully warmed to room temperature. At approximately 20° C. a vigorous exotherm started, and the ice bath was re-applied. The mixture was cooled to room temperature and stirred for 1 h, then the solution was washed with water (100 mL), stirred with 10% aqueous sodium thiosulfate pentahydrate (75 mL) for 10 min, and separated. The organic solution was washed with saturated aqueous sodium bicarbonate and saturated aqueous sodium chloride (75 mL each), dried (Na2SO4), and concentrated to 30 mL volume. The solution was added to a silica gel column (˜400 cc) and eluted with dichloromethane to afford (after very gentle concentration of appropriate fractions) 5-allylcyclopent-2-enone (3.95 g, 75%) as a very pale yellow oil. NMR (CDCl3): δ 7.61 (m, 1 H), 6.12 (m, 1 H), 5.60-5.75 (m, 1 H) 4.90-5.05 (m, 2 H), 2.7-2.80 (m, 1H), 2.45-2.55 (m, 1H), 2.30-2.40 (m, 2 H), 2.05-2.15 (m, 1 H). At approximately 20° C. the solution was washed with water (100 mL) stirred with 10% aqueous sodium thiosulfate pentahydrate (75 mL) for 10 min separated The organic solution was washed with saturated aqueous sodium bicarbonate and saturated aqueous sodium chloride (75 mL each) dried (Na2SO4) concentrated to 30 mL volume The solution was added to a silica gel column (˜400 cc) eluted with dichloromethane to afford ( after very gentle concentration of appropriate fractions) 5-allylcyclopent-2-enone (3.95 g, 75%) as a very pale yellow oil

Conditions: temp:60.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A stirred solution of 5-(propene-3-yl)cyclopent-2-enone (0.428, 3.5 mmol) in nitromethane (2 mL) under nitrogen was treated with DOWEX® 550A-OH resin (0.80 g, rinsed with methanol and partially air dried), and heated to 60° C. for 2 h. The mixture was cooled to room temperature, diluted with dichloromethane (20 mL), and filtered. The filtrate was concentrated in vacuo, redissolved in minimum dichloromethane, and added to a silica gel column (˜100 cc) and eluted with dichloromethane to afford the subject compound (0.368 g, 57%) as a colorless oil. NMR (CDCl3): δ 5.65-5.80 (m, 1 H), 5.00-5.15 (m, 2 H), 4.40-4.50 (m, 2 H), 2.85-3.15 (m, 1 H), 2.30-2.70 (m, 4 H), 1.90-2.20 (m, 3 H). MS (M+1): 183.9. rinsed with methanol and partially air dried), and The mixture was cooled to room temperature diluted with dichloromethane (20 mL) filtered The filtrate was concentrated in vacuo redissolved in minimum dichloromethane added to a silica gel column (˜100 cc) eluted with dichloromethane

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

Procedure: A solution of 5-(propene-3-yl)cyclopent-2-enone (4.28 g, 35 mmol) in dichloromethane (15 mL) was treated with benzyl carbamate (10.6 g, 70 mmol) and bismuth trinitrate pentahydrate (2.2 g, 4.5 mmol), stirred rapidly for 18 h, then diluted with dichloromethane (50 mL). The mixture was filtered through Celite® (rinse with dichloromethane) and the filtrate added directly to a silica gel column (˜550 cc). Elution first with 3:2 petroleum ether/dichloromethane afforded recovered starting material (1.01 g), then 4:1 heptane/ethyl acetate gave the subject compound (4.54 g, 47.5% uncorrected yield) as a pale yellow oil. NMR (CDCl3): δ 7.28 (br s, 5 H), 5.55-5.70 (m, 1 H), 5.03 (br s, 2 H), 4.90-5.10 (m, 2 H), 4.75-4.90 (m, 1 H), 4.10-4.30 (m, 1 H), 2.40-2.80 (m, 2 H), 2.15-2.40 (m, 2 H), 1.85-2.15 (m, 3 H). MS (M+Na): 296.0; MS (M−H2O+1): 256.0 (no M+1 visible). The mixture was filtered through Celite® (rinse with dichloromethane) the filtrate added directly to a silica gel column (˜550 cc) Elution first with 3:2 petroleum ether/dichloromethane afforded recovered 4:1 heptane/ethyl acetate gave the subject compound (4.54 g, 47.5% uncorrected yield) as a pale yellow oil