Dimethyl Sulfoxide → tert-Butyl(R)-1-benzyloxycarbonyl-3-methyl-4-oxopyrrolidine-3-carboxylate

To a solution of oxalyl chloride (1.01 mL, 11.7 mmol) in dichloromethane (40 mL), a solution of dimethyl sulfoxide (1.11 mL, 15.6 mmol) in dichloromethane (5 mL) was added at −78° C., and the mixture was stirred for 10 minutes. After adding a solution of tert-butyl(R)-1-benzyloxycarbonyl-4-hydroxy-3-methylpyrrolidine-3-carboxylate (1.97 g, 5.87 mmol) in dichloromethane (15 mL) and stirring the mixture for 1 hour, triethylamine (5.98 mL, 42.9 mmol) was added, and the mixture was stirred −78° C. for 30 minutes and in an ice bath for 30 minutes. To the reaction mixture were added saturated aqueous solution of ammonium chloride (50 mL) and water (100 mL), and the mixture was extracted with ethyl acetate (200 mL×2). The organic layer was washed with water (100 mL) and saturated aqueous solution of sodium chloride (100 mL), and dried with anhydrous sodium sulfate. The solvent was removed by distillation under reduced pressure, and the residue was purified by silica gel column chromatography (hexane-ethyl acetate=10:1→3:2) to obtain 1.68 g (85.8%) of the title compound as a colorless oily substance.

1. stirringstirring the mixture for 1 hour
2. stirringthe mixture was stirred −78° C. for 30 minutes and in an ice bath for 30 minutes
3. extractionthe mixture was extracted with ethyl acetate (200 mL×2)
4. washThe organic layer was washed with water (100 mL) and saturated aqueous solution of sodium chloride (100 mL)
5. dry with materialdried with anhydrous sodium sulfate
6. customThe solvent was removed by distillation under reduced pressure
7. customthe residue was purified by silica gel column chromatography (hexane-ethyl acetate=10:1→3:2)

ORD record

ord-5919e72d2b054452a36c3ed36730be58

Source dataset

uspto-grants-2009_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07563805B2