Sodium borohydride → 3-Cyclopropyl-2,2-difluoropropan-1-ol

Temperature

0 °C

The solution containing the methyl 3-cyclopropyl-2,2-difluoropropionate from the previous step was diluted with 20 mL of ethanol and cooled to 0° C. under Ar. To this stirred solution was added 605 mg (16 mmol) of sodium borohydride in small portions under Ar. The reaction was stirred in the cold for 1 h and then stored in the freezer for several days. The cold reaction mixture was quenched by the dropwise addition of 2M HCl until no further gas evolution was observed. The reaction was extracted with four portions of ether, the combined organic layers washed with water, brine, dried over Na2SO4 and the solvents removed by distillation at atm. pressure to give a solution of the product in ethanol. This solution was partitioned between pentane and water, the aqueous layer extracted with three portions of pentane, the combined organic layers dried over MgSO4 and the solvents removed by distillation at atm. pressure to give the title compound as a colorless oil:

1. waitstored in the freezer for several days
2. customThe cold reaction mixture
3. customwas quenched by the dropwise addition of 2M HCl until no further gas evolution
4. extractionThe reaction was extracted with four portions of ether
5. washthe combined organic layers washed with water, brine
6. dry with materialdried over Na2SO4
7. customthe solvents removed by distillation at atm
8. custompressure to give a solution of the product in ethanol
9. customThis solution was partitioned between pentane and water
10. extractionthe aqueous layer extracted with three portions of pentane
11. dry with materialthe combined organic layers dried over MgSO4
12. customthe solvents removed by distillation at atm

ORD record

ord-bb80dd49764141128cfa12b39c638d4c

Source dataset

uspto-grants-2003_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06610692B1