(3S)-3-[tert-butyl(dimethyl)silyl]oxypyrrolidin-2-one

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

Procedure: A 60% dispersion of sodium hydride in mineral oil (232 mg, 5.31 mmol) was added to a stirred solution of (S)-3-((tert-butyldimethylsilyl)oxy)pyrrolidin-2-one (762 mg, 3.54 mmol, intermediate G) in THF (7 mL) at 0° C. After 15 min, a solution of 1-(bromomethyl)-4-(difluoromethyl)benzene (980 mg, 4.43 mmol) in THF (7 mL) was added to the reaction mixture. The resulting mixture was stirred at room temperature for 6 h. The reaction was carefully quenched with several grams of ice pellets. The resulting mixture was extracted with EtOAc. The combined organic layers were washed with water, dried over sodium sulfate, filtered and concentrated in vacuo. The crude reaction mixture was purified using silica gel column chromatography (0-30% EtOAc/hexanes) to afford the desired product (440 mg, 35% yield) as a white solid: LCMS (M+H)+ 356.3; 1H NMR (500 MHz, chloroform-d) δ 7.49 (d, J=8.1 Hz, 2H), 7.35 (d, J=7.9 Hz, 2H), 6.65 (br. t, J=1.0 Hz, 1H), 4.56-4.44 (m, 2H), 4.38 (t, J=7.5 Hz, 1H), 3.27 (ddd, J=9.7, 8.7, 3.4 Hz, 1H), 3.13 (dt, J=9.7, 7.4 Hz, 1H), 2.36-2.27 (m, 1H), 1.98-1.90 (m, 1H), 0.96 (br. s., 9H), 0.22-0.20 (m, 3H), 0.20-0.18 (m, 3H). The reaction was carefully quenched with several grams of ice pellets The resulting mixture was extracted with EtOAc The combined organic layers were washed with water dried over sodium sulfate filtered concentrated in vacuo The crude reaction mixture was purified

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

Procedure: (S)-3-((tert-butyldimethylsilyl)oxy)pyrrolidin-2-one (5 g, 23.22 mmol, intermediate G) was dissolved in anhydrous THF (46.4 ml) and the reaction mixture was cooled to 0° C. under a nitrogen atmosphere. Sodium hydride (1.393 g, 34.8 mmol) was then added in one portion and the reaction mixture was allowed to stir for 5 min before the dropwise addition of 1-(bromomethyl)-4-methylbenzene (5.37 g, 29.0 mmol) in anhydrous THF (46.4 ml). The reaction was allowed to stir at 0° C. for 5 min, then the cooling bath was removed and mixture was allowed to warm to rt overnight. The reaction was cautiously quenched with water (100 mL) and then extracted with ethyl acetate (3×100 mL). The combined organic layers were then washed with brine (200 mL) and dried (MgSO4). Evaporation of the solvent in vacuo gave the crude product (9.6 g, oil) which was then purified by silica gel chromatography (330 g of silica) eluting with a gradient of 0% to 20% ethyl acetate in hexanes to provide 6.53 g (88%) of the desired product. LC/MS (Conditions B), RT=4.320 min, (M+H)+=320.3. 1H NMR (400 MHz, chloroform-d) δ 7.15 (s, 4H), 4.42 (s, 2H), 4.37 (t, J=7.6 Hz, 1H), 3.32-3.18 (m, 1H), 3.10 (dt, J=9.7, 7.5 Hz, 1H), 2.36 (s, 3H), 2.29 (dtd, J=12.6, 7.6, 3.1 Hz, 1H), 1.97-1.84 (m, 1H), 0.95 (s, 9H), 0.20 (d, J=10.3 Hz, 6H). the cooling bath was removed to warm to rt overnight The reaction was cautiously quenched with water (100 mL) extracted with ethyl acetate (3×100 mL) The combined organic layers were then washed with brine (200 mL) dried (MgSO4) Evaporation of the solvent in vacuo gave the crude product (9.6 g, oil) which was then purified by silica gel chromatography (330 g of silica) eluting with a gradient of 0% to 20% ethyl acetate in hexanes

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

Procedure: (S)-3-((tert-butyldimethylsilyl)oxy)pyrrolidin-2-one (5 g, 23.22 mmol, intermediate G) was dissolved in anhydrous THF (46.4 ml) and the reaction mixture was cooled to 0° C. under a nitrogen atmosphere. Sodium hydride (1.393 g, 34.8 mmol) was then added in one portion and the reaction mixture was allowed to stir for 5 min before the dropwise addition of 1-(bromomethyl)-4-methylbenzene (5.37 g, 29.0 mmol) in anhydrous THF (46.4 ml). The reaction was allowed to stir at 0° C. for 5 min, then the cooling bath was removed and mixture was allowed to warm to rt overnight. The reaction was cautiously quenched with water (100 mL) and then extracted with ethyl acetate (3×100 mL). The combined organic layers were then washed with brine (200 mL) and dried (MgSO4). Evaporation of the solvent in vacuo gave the crude product (9.6 g, oil) which was then purified by silica gel chromatography (330 g of silica) eluting with a gradient of 0% to 20% ethyl acetate in hexanes to provide 6.53 g (88%) of the desired product. LC/MS (Conditions B), RT=4.320 min, (M+H)+=320.3. 1H NMR (400 MHz, chloroform-d) δ 7.15 (s, 4H), 4.42 (s, 2H), 4.37 (t, J=7.6 Hz, 1H), 3.32-3.18 (m, 1H), 3.10 (dt, J=9.7, 7.5 Hz, 1H), 2.36 (s, 3H), 2.29 (dtd, J=12.6, 7.6, 3.1 Hz, 1H), 1.97-1.84 (m, 1H), 0.95 (s, 9H), 0.20 (d, J=10.3 Hz, 6H). the cooling bath was removed to warm to rt overnight The reaction was cautiously quenched with water (100 mL) extracted with ethyl acetate (3×100 mL) The combined organic layers were then washed with brine (200 mL) dried (MgSO4) Evaporation of the solvent in vacuo gave the crude product (9.6 g, oil) which was then purified by silica gel chromatography (330 g of silica) eluting with a gradient of 0% to 20% ethyl acetate in hexanes

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

Procedure: A stirred solution of commercial (S)-3-hydroxypyrrolidin-2-one (5 g, 49.5 mmol) in DCM (198 ml) was treated with DMAP (0.199 g, 1.632 mmol), imidazole (6.73 g, 99 mmol), and TBDMS-Cl (8.94 g, 59.3 mmol). The reaction mixture was stirred at rt for 16 h, and then was washed with a satd. NaHCO3 solution. The organic layer was concentrated and the crude reaction product was purified by silica gel chromatogpraphy eluting with 50% ethyl acetate in petroleum ether. The desired product was isolated as a white solid (8.1 g, 76%). LC/MS (M+H)+=216.2. 1H NMR (400 MHz, chloroform-d) δ 6.40 (br. s., 1H), 4.26 (t, J=7.8 Hz, 1H), 3.42-3.34 (m, 1H), 3.29-3.21 (m, 1H), 2.36 (dtd, J=12.7, 7.3, 3.3 Hz, 1H), 2.07-1.96 (m, 1H), 0.91 (s, 9H), 0.15 (d, J=7.0 Hz, 6H). was washed with a satd The organic layer was concentrated the crude reaction product was purified by silica gel chromatogpraphy eluting with 50% ethyl acetate in petroleum ether

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

Procedure: In one portion, 11.6 g of (S)-3-[[(1,1-dimethyl-ethyl)dimethylsilyl]oxy]-2-pyrrolidinone was added to a suspension of 2.35 g of 60% sodium hydride in mineral oil in 400 ml of tetrahydrofuran which was cooled to 0° C. The resulting solution was stirred at room temperature until solution was complete, then recooled to 0° C. An 80% solution of propargyl bromide in toluene (8.5 ml) was added and the resulting solution was stirred overnight. The solution was diluted with dichloromethane, washed with water, dried and concentrated in vacuo. The residue was purified by chromatography (silica gel), giving (S)-3-[[(1,1-dimethylethyl)-dimethylsilyl]oxy]-1-(2-propynyl)-2-pyrrolidinone, [α]D26 =-44° (dichloromethane); mp 35°-36° C. recooled to 0° C the resulting solution was stirred overnight washed with water dried concentrated in vacuo The residue was purified by chromatography (silica gel)

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

Procedure: A solution of 11.5 g of potassium tert-butoxide in 300 ml of dimethylformamide was cooled to -20° C. An 18 g portion of (S)-3-[[(1,1-dimethylethyl)dimethylsilyl]-oxy]-2-pyrrolidinone was added and the mixture stirred at -20° C. for 30 minutes. A 12 ml portion of 80% propargyl bromide in toluene was added and the reaction was allowed to warm to room temperature and was stirred for 1 hour. Water was added and the mixture was extracted with 5×100 ml of ether and 3×100 ml of dichloromethane. The extracts were combined, backwashed with water, dried and concentrated in vacuo, giving 15.8 g of (S)-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-1-(2-propynyl)-2-pyrrolidinone [α]D260 =-44° (dichloromethane); mp 35°-36° C. to warm to room temperature was stirred for 1 hour the mixture was extracted with 5×100 ml of ether and 3×100 ml of dichloromethane dried concentrated in vacuo

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

Procedure: A mixture of 14 g of (S)-3-hydroxy-2-pyrrolidinone, 45 g of tert-butyldimethylsilyl chloride, 50 ml of triethylamine and 500 ml of dichloromethane was stirred overnight. The solution was washed four times with water, once with brine, dried and concentrated in vacuo. The residue was dissolved in 500 ml of methanol, refluxed overnight and concentrated in vacuo. The residue was purified by chromatography (silica gel), giving 21.5 g of (S)-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-2-pyrrolidinone; [α]D260 =-52° (dichloromethane); mp 48°-49° C. The solution was washed four times with water once with brine, dried concentrated in vacuo The residue was dissolved in 500 ml of methanol refluxed overnight concentrated in vacuo The residue was purified by chromatography (silica gel)

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

Procedure: In an ice bath, 570 mg of imidazole and 947 mg of t-butyldimethylsilyl chloride were added to a dimethylformamide (5 ml) solution of 503 mg of (3S)-3-hydroxypyrrolidin-2-one, and stirred at room temperature for 1 hour. Water was added to the reaction liquid, extracted with ethyl acetate, the organic layer was washed with water and saturated saline water, and dried. The solvent was evaporated away under reduced pressure to obtain 452 mg of the entitled compound as a pale yellow oil. extracted with ethyl acetate the organic layer was washed with water and saturated saline water dried The solvent was evaporated away under reduced pressure

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

Procedure: In one portion, 11.6 g of (S)-3-[[(1,1-dimethyl-ethyl)dimethylsilyl]oxy]-2-pyrrolidinone was added to a suspension of 2.35 g of 60% sodium hydride in mineral oil in 400 ml of tetrahydrofuran which was cooled to 0° C. The resulting solution was stirred at room temperature until solution was complete, then recooled to 0° C. An 80% solution of propargyl bromide in toluene (8.5 ml) was added and the resulting solution was stirred overnight. The solution was diluted with dichloromethane, washed with water, dried and concentrated in vacuo. The residue was purified by chromatography (silica gel), giving (S)-3-[[(1,1-dimethylethyl)-dimethylsilyl]oxy]-1-(2-propynyl)-2-pyrrolidinone, [α]D26 =-44° (dichloromethane); mp 35°-36° C. recooled to 0° C the resulting solution was stirred overnight washed with water dried concentrated in vacuo The residue was purified by chromatography (silica gel)

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

Procedure: A solution of 11.5 g of potassium tert-butoxide in 300 ml of dimethylformamide was cooled to -20° C. An 18 g portion of (S)-3-[[(1,1-dimethylethyl)dimethylsilyl]-oxy]-2-pyrrolidinone was added and the mixture stirred at -20° C. for 30 minutes. A 12 ml portion of 80% propargyl bromide in toluene was added and the reaction was allowed to warm to room temperature and was stirred for 1 hour. Water was added and the mixture was extracted with 5×100 ml of ether and 3×100 ml of dichloromethane. The extracts were combined, backwashed with water, dried and concentrated in vacuo, giving 15.8 g of (S)-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-1-(2-propynyl)-2-pyrrolidinone [α]D26° =-44° (dichloromethane); mp 35°-36° C. to warm to room temperature was stirred for 1 hour the mixture was extracted with 5×100 ml of ether and 3×100 ml of dichloromethane dried concentrated in vacuo

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

Procedure: A mixture of 14 g of (S)-3-hydroxy-2-pyrrolidinone, 45 g of tert-butyldimethylsilyl chloride, 50 ml of triethylamine and 500 ml of dichloromethane was stirred overnight. The solution was washed four times with water, once with brine, dried and concentrated in vacuo. The residue was dissolved in 500 ml of methanol, refluxed overnight and concentrated in vacuo. The residue was purified by chromatography (silica gel), giving 21.5 g of (S)-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-2-pyrrolidinone; [α]D26° =-52° (dichloromethane); mp 48°-49° C. The solution was washed four times with water once with brine, dried concentrated in vacuo The residue was dissolved in 500 ml of methanol refluxed overnight concentrated in vacuo The residue was purified by chromatography (silica gel)

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

Procedure: In one portion, 11.6 g of (S)-3-[[(1,1-dimethyl-ethyl)dimethylsilyl]oxy]-2-pyrrolidinone was added to a suspension of 2.35 g of 60% sodium hydride in mineral oil in 400 ml of tetrahydrofuran which was cooled to 0° C. The resulting solution was stirred at room temperature until solution was complete, then recooled to 0° C. An 80% solution of propargyl bromide in toluene (8.5 ml) was added and the resulting solution was stirred overnight. The solution was diluted with dichloromethane washed with water, dried and concentrated in vacuo. The residue was purified by chromatography (silica gel), giving (S)-3-[[(1,1-dimethylethyl)dimethylsilyl]oxy]-1-(2-propynyl)-2-pyrrolidinone, [α]D26 =-44° (dichloromethane); mp 35°-36° C. recooled to 0° C the resulting solution was stirred overnight washed with water dried concentrated in vacuo The residue was purified by chromatography (silica gel)