Methanol → Methyl 6-oxabicyclo[3.1.0]hexane-3-carboxylate

3-Cyclopentenecarboxylic acid (J. Org. Chem., 1984, Vol. 49, p. 928) (2.42 g) was dissolved in methanol (8 ml) and 2,2-dimethoxypropane (32 ml), and trimethylsilyl chloride (253 μl) was added dropwise to stir the mixture at room temperature for 6.5 hours. The solvent was distilled off under reduced pressure, and the residue was dissolved in dichloromethane (50 ml), to which m-chloroperbenzoic acid (70%, 4.93 g) was added under ice cooling. After the mixture was heated to room temperature and stirred for 5 hours, a saturated aqueous solution of sodium hydrogencarbonate was added to separate an organic layer. The organic layer was washed with a saturated aqueous solution of sodium hydrogencarbonate and then dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure, and the residue was purified by column chromatography on silica gel (hexane:ethyl acetate=2:1) to obtain the title compound (1.59 g) as a colorless oil.

1. distillationThe solvent was distilled off under reduced pressure
2. dissolutionthe residue was dissolved in dichloromethane (50 ml), to which m-chloroperbenzoic acid (70%, 4.93 g)
3. additionwas added under ice cooling
4. temperatureAfter the mixture was heated to room temperature
5. stirringstirred for 5 hours
6. additiona saturated aqueous solution of sodium hydrogencarbonate was added
7. customto separate an organic layer
8. washThe organic layer was washed with a saturated aqueous solution of sodium hydrogencarbonate
9. dry with materialdried over anhydrous sodium sulfate
10. concentrationThe organic layer was concentrated under reduced pressure
11. customthe residue was purified by column chromatography on silica gel (hexane:ethyl acetate=2:1)

ORD record

ord-6480db3011354424a482fe95a102c94c

Source dataset

uspto-grants-2007_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07192968B2