Hydrochloric Acid → HCID 22907960, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of oxalyl chloride (5.45 ml) in dichloromethane (100 ml) was added dropwise a solution of dimethyl sulfoxide (9.67 ml) in dichloromethane (10 ml) at -78° C. After stirring at -78° C. for 10 minutes, to the mixture was added dropwise a solution of (2S)-1-allyloxycarbonyl-2-hydroxymethylpyrrolidine (10.41 g) in dichloromethane (20 ml). After stirring at -78° C. for 10 minutes, to the mixture was added dropwise triethylamine (39.6 ml) and the resulting mixture was allowed to warm to 0° C. and diluted with ethyl acetate (400 ml) and brine (200 ml). After adjusting pH to around 5 with 4N hydrochloric acid, the organic layer was separated, washed with brine and dried over magnesium sulfate. Evaporation of the solvent gave an oil of 1-allyloxycarbonyl-2-formylpyrrolidine (8.72 g), which was dissolved in toluene (100 ml). To this solution was added 3-triphenylphosphoranylidenebutan-2-one (17.4 g) and the mixture was allowed to stand at ambient temperature for 5 days. Evaporation of the solvent gave a residue which was taken up into ethyl acetate. The resulting precipitate was removed by filtration and the filtrate was evaporated in vacuo. The residue was chromatographed on silica gel (300 ml) eluting with a mixture of n-hexane and ethyl acetate (9:1 - 6:4 V/V) to give (2S)-1-allyloxycarbonyl-2-(2-methyl-3-oxo-1-butenyl)pyrrolidine (9.00 g).

Provenance & Evidence