benzyl 2-(triphenyl-lambda5-phosphanylidene)acetate

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:

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

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

Procedure: 1,1,1-Trifluoroacetone (680 mg, 6.1 mmol) was added to an ambient temperature solution of benzyl (triphenylphosphoranylidene)acetate (2.5 g, 6.1 mmol) in methylene chloride (10 mL). After stirring in a sealed tube for 72 h, the reaction mixture was concentrated in vacuo. Chromatography over silica eluting with 0-20% ethyl acetate/hexane afforded benzyl 4,4,4-trifluoro-3-methylbut-2-enoate. the reaction mixture was concentrated in vacuo

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

Procedure: The solution of methyl 3-(2-formylpyrrol-1-yl)benzoate (1.0 g) and benzyl (triphenylphosphoranylidene)acetate (1.8 g) in tetrahydrofuran (10 ml) were heated under reflux for 30 hours. After evaporating the solvent, the residue was purified by column chromatography on silica gel eluting with toluene. The fractions containing the desired product were collected and evaporated in vacuo to give methyl 3-[2-((E)-2-benzyloxycarbonylethenyl)pyrrol-1-yl)benzoate (0.77 g) as an oil. under reflux for 30 hours After evaporating the solvent the residue was purified by column chromatography on silica gel eluting with toluene The fractions containing the desired product were collected evaporated in vacuo

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 763 mg (2.0 mmol) of benzhydryl (2S,3R,5R)-3-formyl-3-methyl-7-oxo-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylate were dissolved in 15 ml of THF under argon, treated with 821 mg (2.0 mmol) of benzyloxycarbonylmethylene-triphenylphosphorane and the orange solution was stirred at 50° C. for 2 hours. It was left to cool to room temperature, the solvent was removed on a rotary evaporator and the red-brown oil was chromatographed over silica gel (particle size 0.040-0.063 mm) with ethyl acetate:hexane (9:16) as the eluent. Yield: 800 mg (78%) of orange foam IR (film): 1782, 1746, 1721, 1649, 985 cm-1MS: (M+H)+ 514.3 1H-NMR- (250MHz, CDCl3): δ[ppm]=1.33(s,3H), 3.11 (dd,1H,J=16Hz, 1.6Hz, 6-H), 3.56(dd,1H,J=16Hz, 4.2Hz, 6-H), 4.78(s,1H,2-H), 5.20(s,2H), 5.36(dd,1H, J=1.6Hz, 4.2Hz, 5-H), 6.01(d,1H,J=15Hz,=CH), 6.93(s,1H,CHPh2), 7.12(d,1H,J=15Hz, =CH), 7.30-7.43(m,15H,Ph). It was left to cool to room temperature the solvent was removed on a rotary evaporator the red-brown oil was chromatographed over silica gel (particle size 0.040-0.063 mm) with ethyl acetate:hexane (9:16) as the eluent

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 763 mg (2.0 mmol) of benzhydryl (2S,3R,5R)-3-formyl-3-methyl-7-oxo-4-thia-1-aza-bicyclo[3.2.0]heptane-2-carboxylate were dissolved in 15 ml of THF under argon, treated with 821 mg (2.0 mmol) of benzyloxycarbonylmethylene-triphenylphosphorane and the orange solution was stirred at 50° C. for 2 hours. It was left to cool to room temperature, the solvent was removed on a rotary evaporator and the red-brown oil was chromatographed over silica gel (particle size 0.040-0.063 mm) with ethyl acetate:hexane (9:16) as the eluent. Yield: 800 mg (78%) of orange foam IR (film): 1782, 1746, 1721, 1649, 985 cm-1MS: (M+H)+ 514.3 1H-NMR- (250MHz, CDCl3): δ[ppm]=1.33(s,3H), 3.11 (dd,1H,J=16Hz, 1.6Hz, 6-H), 3.56(dd,1H,J=16Hz, 4.2Hz, 6-H), 4.78(s,1H,2-H), 5.20(s,2H), 5.36(dd,1H, J=1.6Hz, 4.2Hz, 5-H), 6.01(d,1H,J=15Hz,=CH), 6.93(s,1H,CHPh2), 7.12(d,1H,J=15Hz, =CH), 7.30-7.43(m,15H,Ph). It was left to cool to room temperature the solvent was removed on a rotary evaporator the red-brown oil was chromatographed over silica gel (particle size 0.040-0.063 mm) with ethyl acetate:hexane (9:16) as the eluent

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

Procedure: A 22.9 g quantity of benzyl bromoacetate was dissolved in 100 ml of dry benzene. A 26.2 g quantity of triphenylphosphine was added thereto at room temperature and stirred overnight. The precipitated solids were collected by filtration, washed with benzene and dissolved in 250 ml of dichloromethane. A 14 ml quantity of triethylamine was added with ice-cooling and stirred with ice-cooling for 30 minutes and at room temperature for a further 30 minutes. The reaction mixture was transferred to a separating funnel, washed with water and dried over magnesium sulfate. The solvent was distilled off and diethyl ether was added to the residue. The resulting precipitate was collected by filtration to provide the title compound as white crystals (yield 41%). The precipitated solids were collected by filtration washed with benzene dissolved in 250 ml of dichloromethane A 14 ml quantity of triethylamine was added with ice- cooling stirred with ice- cooling for 30 minutes and at room temperature for a further 30 minutes The reaction mixture was transferred to a separating funnel washed with water dried over magnesium sulfate The solvent was distilled off diethyl ether was added to the residue The resulting precipitate was collected by filtration

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

Procedure: A 22.9 g quantity of benzyl bromoacetate was dissolved in 100 ml of dry benzene. A 26.2 g quantity of triphenylphosphine was added thereto at room temperature and stirred overnight. The precipitated solids were collected by filtration, washed with benzene and dissolved in 250 ml of dichloromethane. A 14 ml quantity of triethylamine was added with ice-cooling and stirred with ice-cooling for 30 minutes and at room temperature for a further 30 minutes. The reaction mixture was transferred to a separating funnel, washed with water and dried over magnesium sulfate. The solvent was distilled off and diethyl ether was added to the residue. The resulting precipitate was collected by filtration to provide the title compound as white crystals (yield 41%). The precipitated solids were collected by filtration washed with benzene dissolved in 250 ml of dichloromethane A 14 ml quantity of triethylamine was added with ice- cooling stirred with ice- cooling for 30 minutes and at room temperature for a further 30 minutes The reaction mixture was transferred to a separating funnel washed with water dried over magnesium sulfate The solvent was distilled off diethyl ether was added to the residue The resulting precipitate was collected by filtration

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

Procedure: A mixture of (4RS)-1-(tert-butyl-dimethylsilyl)-4-(2-oxoethyl)-2-oxoazetidine (240 mg) and benzyl triphenylphosphoranylidene-acetate (521 mg) in dichloromethane (5 ml) was heated under refluxing for one hour. After removal of the solvent, the residue was chromatographed on silica gel (7 g) eluting with a mixture of dichloromethane and acetone (50:1) to give benzyl 4-[(2RS)-1-(tert-butyl-dimethylsilyl)-4-oxoazetidin-2-yl]but-2-enoate (373 mg) as an oil. was heated under refluxing for one hour After removal of the solvent the residue was chromatographed on silica gel (7 g) eluting with a mixture of dichloromethane and acetone (50:1)