2-phenylcyclopentan-1-one

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

Procedure: Scheme IA, step A: 2-Phenyl-cyclopentanone (prepared according to R. Sudha et. al. J. Org. Chem., 61, 1877-1879, 1996) (1.0 g, 6.2 mmol) was dissolved in 20 mL of absolute ethanol. To this solution was added sodium hydroxide (0.5 g, 12.5 mmol) dissolved in 10 mL water followed by hydroxylamine hydrochloride (0.65 g, 9.36 mmol) and stirred overnight at room temperature. The reaction was diluted with water and the precipitate collected by filtration. The white solid was vacuum oven-dried at 35° C. for 30 minutes to give 0.75 g (69%) of the title compound. The NMR was consistent with the assigned structure. the precipitate collected by filtration oven-dried at 35° C. for 30 minutes

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

Procedure: Scheme IA, step A: 2-Phenyl-cyclopentanone (prepared according to R. Sudha et. al. J. Org. Chem., 61, 1877-1879, 1996) (1.0 g, 6.2 mmol) was dissolved in 20 mL of absolute ethanol. To this solution was added sodium hydroxide (0.5 g, 12.5 mmol) dissolved in 10 mL water followed by hydroxylamine hydrochloride (0.65 g, 9.36 mmol) and stirred overnight at room temperature. The reaction was diluted with water and the precipitate collected by filtration. The white solid was vacuum oven-dried at 35° C. for 30 minutes to give 0.75 g (69%) of the title compound. The NMR was consistent with the assigned structure. the precipitate collected by filtration oven-dried at 35° C. for 30 minutes

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

Procedure: To a slurry of 60% NaH (125 mg, 3.12 mmol) in DME (3571 μL) at 0° C. was added 2-phenylcyclopentanone (500 mg, 3.12 mmol). After stirring for 1 h, MeI (898 μL, 14.36 mmol) was added, and the solution heated to reflux for 2 h. The reaction was poured onto ice and extracted 3 times into Et2O. The organic extracts were washed with brine, dried over MgSO4, filtered and concentrated in vacuo. Applied to Silica gel and eluted with an EtOAc/Hex gradient to afford 2-methyl-2-phenylcyclopentanone (401.7 mg, 2.305 mmol, 73.9% yield). LC-MS (M+H)+=175.1. 1H NMR (500 MHz, CDCl3) δ ppm 7.29-7.37 (4H, m), 7.20-7.24 (1H, m), 2.54 (1H, dt, J=12.51, 6.26 Hz), 2.34 (2H, t, J=7.63 Hz), 1.82-2.05 (3H, m), 1.38 (3H, s). the solution heated to reflux for 2 h The reaction was poured onto ice extracted 3 times into Et2O The organic extracts were washed with brine dried over MgSO4 filtered concentrated in vacuo Applied to Silica gel and eluted with an EtOAc/Hex gradient

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

Procedure: A solution of 2-phenylcyclopentanone (19.995 g, 125 mmol) and N-(chlorocarbonyl)isocyanate (23.70 g, 225 mmol) was stirred at 58° C. for 1 h and at 130° C. for 45 min. The resulting tarrified reaction mixture was dissolved in ethyl acetate and neutralized with saturated aqueous sodium bicarbonate solution. The organic layer was dried over anhydrous magnesium sulfate and filtered. The product was purified by column chromatography on silica gel to give 7-phenyl-6,7-dihydrocyclopenta[e][1,3]oxazine-2,4(3H,5H)-dione (3.751 g, 16.36 mmol, 13% yield) as brownish solid. LC-MS (M+H)+=230.0. 1H NMR (500 MHz, CDCl3) δ ppm 8.34 (1H, br s), 7.35 (2H, t, J=7.3 Hz), 7.27-7.32 (1H, m), 7.18 (2H, d, J=7.3 Hz), 4.20 (1H, t, J=7.6 Hz), 2.82-2.91 (1H, m), 2.61-2.79 (2H, m), 2.11-2.21 (1H, m). The organic layer was dried over anhydrous magnesium sulfate filtered The product was purified by column chromatography on silica gel

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

Procedure: A solution of 2-phenylcyclopentanone (19.995 g, 125 mmol) and N-(chlorocarbonyl)isocyanate (23.70 g, 225 mmol) was stirred at 58° C. for 1 h and at 130° C. for 45 min. The resulting tarrified reaction mixture was dissolved in ethyl acetate and neutralized with saturated aqueous sodium bicarbonate solution. The organic layer was dried over anhydrous magnesium sulfate and filtered. The product was purified by column chromatography on silica gel to give 7-phenyl-6,7-dihydrocyclopenta[e][1,3]oxazine-2,4(3H,5H)-dione (3.751 g, 16.36 mmol, 13% yield) as brownish solid. LC-MS (M+H)+=230.0. 1H NMR (500 MHz, CDCl3) δ ppm 8.34 (1H, br s), 7.35 (2H, t, J=7.3 Hz), 7.27-7.32 (1H, m), 7.18 (2H, d, J=7.3 Hz), 4.20 (1H, t, J=7.6 Hz), 2.82-2.91 (1H, m), 2.61-2.79 (2H, m), 2.11-2.21 (1H, m). The organic layer was dried over anhydrous magnesium sulfate filtered The product was purified by column chromatography on silica gel

Conditions: temp:-78.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of diisopropylamine (6.62 mL, 46.8 mmol) in THF (200 mL) at −78° C. was added a 1.6 M solution of n-butyllithium in hexanes (29.3 mL, 46.8 mmol). The solution was stirred for 30 min at −78° C. and treated with a solution of 2-phenylcyclopentanone (5 g, 31.2 mmol) in 50 mL of dry THF. After stirring for 30 min at −78° C., ethyl carbonocyanidate (3.36 mL, 34.3 mmol) was added to the reaction mixture. The resulting solution was warmed to 25° C. with stirring over 3 h. The reaction mixture was quenched with 10 mL of water, washed with brine, dried over anhydrous sodium sulfate, concentrated in vacuum, and purified by column chromatography on silica gel to afford ethyl 2-oxo-3-phenylcyclopentanecarboxylate (5.3 g, 22.82 mmol, 73% yield) as colorless oil. LC-MS (M+K)+=273.2. 1H NMR (500 MHz, CDCl3) δ ppm 7.32-7.39 (2H, m), 7.25-7.31 (1H, m), 7.19-7.25 (2H, m), 4.18-4.32 (2H, m), 3.29-3.55 (2H, m), 1.87-2.62 (4H, m), 1.28-1.39 (3H, m). After stirring for 30 min at −78° C. The resulting solution was warmed to 25° C. with stirring over 3 h The reaction mixture was quenched with 10 mL of water washed with brine dried over anhydrous sodium sulfate concentrated in vacuum purified by column chromatography on silica gel

Conditions: temp:40.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 30% hydrogen peroxide (23 mL, 149 mmol) and 85% formic acid (100 mL, 2619 mmol) was heated at 40° C. for 15 minutes. The mixture was carefully added to cyclopentenylbenzene (21.49 g, 149 mmol) and the resulting two-phase system was vigorously stirred at room temperature for 4 h. An exothermic reaction was observed in the beginning. In the end of the stirring the solution became homogeneous. The reaction mixture was carefully quenched with saturated aqueous solution of sodium bicarbonate. The product was extracted with ether. The combined etherial layers were dried over anhydrous magnesium sulfate and filtered. The solvent was removed in vacuum and the product was purified by column chromatography on silica gel to give 2-phenylcyclopentanone (19.995 g, 125 mmol, 84% yield) as brown oil. LC-MS (M+H)+=161.0. 1H NMR (500 MHz, CDCl3) δ ppm 7.38 (1H, t, J=7.3 Hz), 7.30-7.35 (2H, m), 7.19 (2H, d, J=7.3 Hz), 3.28-3.37 (1H, m), 2.71 (1H, td, J=4.6, 2.7 Hz), 2.58-2.63 (1H, m), 2.43-2.55 (1H, m), 2.29 (1H, ddd, J=19.0, 10.5, 9.0 Hz), 2.07-2.21 (1H, m), 1.88-1.99 (1H, m). An exothermic reaction The reaction mixture was carefully quenched with saturated aqueous solution of sodium bicarbonate The product was extracted with ether The combined etherial layers were dried over anhydrous magnesium sulfate filtered The solvent was removed in vacuum the product was purified by column chromatography on silica gel

Conditions: temp:40.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 30% hydrogen peroxide (23 mL, 149 mmol) and 85% formic acid (100 mL, 2619 mmol) was heated at 40° C. for 15 minutes. The mixture was carefully added to cyclopentenylbenzene (21.49 g, 149 mmol) and the resulting two-phase system was vigorously stirred at room temperature for 4 h. An exothermic reaction was observed in the beginning. In the end of the stirring the solution became homogeneous. The reaction mixture was carefully quenched with saturated aqueous solution of sodium bicarbonate. The product was extracted with ether. The combined etherial layers were dried over anhydrous magnesium sulfate and filtered. The solvent was removed in vacuum and the product was purified by column chromatography on silica gel to give 2-phenylcyclopentanone (19.995 g, 125 mmol, 84% yield) as brown oil. LC-MS (M+H)+=161.0. 1H NMR (500 MHz, CDCl3) δ ppm 7.38 (1H, t, J=7.3 Hz), 7.30-7.35 (2H, m), 7.19 (2H, d, J=7.3 Hz), 3.28-3.37 (1H, m), 2.71 (1H, td, J=4.6, 2.7 Hz), 2.58-2.63 (1H, m), 2.43-2.55 (1H, m), 2.29 (1H, ddd, J=19.0, 10.5, 9.0 Hz), 2.07-2.21 (1H, m), 1.88-1.99 (1H, m). An exothermic reaction The reaction mixture was carefully quenched with saturated aqueous solution of sodium bicarbonate The product was extracted with ether The combined etherial layers were dried over anhydrous magnesium sulfate filtered The solvent was removed in vacuum the product was purified by column chromatography on silica gel

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

Procedure: A solution of 2-phenylcyclopentanone (19.995 g, 125 mmol) and carbonisocyanatidic chloride (23.70 g, 225 mmol) was stirred at 58° C. for 1 h and at 130° C. for 45 min. The resulting tar was dissolved in ethyl acetate and neutralized with saturated aqueous sodium bicarbonate solution. The organic layer was dried over anhydrous magnesium sulfate and filtered. The product was purified by column chromatography on silica gel to give 7-phenyl-6,7-dihydrocyclopenta[e][1,3]oxazine-2,4(3H,5H)-dione (3.751 g, 16.36 mmol, 13% yield) as a brownish solid. LC-MS (M+H)+=230.0. 1H NMR (500 MHz, CDCl3) δ ppm 8.34 (1H, br s), 7.35 (2H, t, J=7.3 Hz), 7.27-7.32 (1H, m), 7.18 (2H, d, J=7.3 Hz), 4.20 (1H, t, J=7.6 Hz), 2.82-2.91 (1H, m), 2.61-2.79 (2H, m), 2.11-2.21 (1H, m). The organic layer was dried over anhydrous magnesium sulfate filtered The product was purified by column chromatography on silica gel