Methanol → Ethyl [1-(2-bromoethyl)cyclopropyl]acetate

Under argon, 30.86 ml (30.86 mmol) of borane/THF complex solution (1 M in THF) are added dropwise at 0° C. to a solution of 14.00 g (90.79 mmol) of ethyl (1-vinylcyclopropyl)acetate (Example 2A) in 80 ml of anhydrous THF. After 30 min at 0° C., the mixture is stirred at room temperature for a further 30 min, and 0.20 ml (5.00 mmol) of methanol is then added. At −5° C., 5.61 ml (108.94 mmol) of bromine and 26.98 g (150.0 mmol) of sodium methoxide solution (30% strength in methanol) are then successively added dropwise to the reaction mixture. After the mixture has reached room temperature, 30 ml of saturated sodium bicarbonate solution are added. The reaction mixture is extracted three times with tert-butyl methyl ether. The combined organic phases are washed with saturated sodium chloride solution and dried over anhydrous magnesium sulfate. Removal of the solvent and kugelrohr distillation of the residue at 180° C. and 0.04 mbar gives 12.90 g (60% of theory) of the title compound as a yellow oil which, on storage in a fridge, turns very dark over a period of a few hours.

1. customhas reached room temperature
2. extractionThe reaction mixture is extracted three times with tert-butyl methyl ether
3. washThe combined organic phases are washed with saturated sodium chloride solution
4. dry with materialdried over anhydrous magnesium sulfate
5. customRemoval of the solvent and kugelrohr distillation of the residue at 180° C.

ORD-Eintrag

ord-4c56273eca5c4ada94f6f7a5467a1ee5

Quelldatensatz

uspto-grants-2012_05

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08168821B2