Reaction #669936

Reaction equation

sodium cyclopentadienylide

1-bromo-2-fluoroethane

sodium hydroxide

hydrogen peroxide

2-methyl-2-butene

→

(RS)-3-(2-fluoroethyl)-3-cyclopenten-1-ol

Yield 16.0%

Solvents

tetrahydrofuran

Conditions

Workup

1. 1
   Temperaturecooling and under nitrogen
2. 2
   OtherThe resulting reaction liquid
3. 3
   Filtrationwas filtered with cerite, and the filtrate
4. 4
   workup.ADDITIONwas added under ice-
5. 5
   Temperaturecooling and under nitrogen stream to a tetrahydrofuran solution of disiamylborane
6. 6
   Otherprepared
7. 7
   workup.STIRRINGthe resulting mixture was stirred for 8 hours
8. 8
   Temperaturecooling to the reaction liquid
9. 9
   Otherobtained above, and the resulting mixture
10. 10
    workup.STIRRINGwas stirred for 1 hour
11. 11
    OtherThe reaction liquid
12. 12
    Otherthus obtained
13. 13
    Extractionwas extracted two times with diethyl ether
14. 14
    WashThe combined ether layer was washed with saturated aqueous sodium chloride solution
15. 15
    Dryingdried over anhydrous magnesium sulfate
16. 16
    workup.DISTILLATIONthe solvent was distilled off under reduced pressure
17. 17
    OtherThe residue obtained

Procedure

To 25 ml of 2 M tetrahydrofuran solution of sodium cyclopentadienylide was added under ice-cooling and under nitrogen stream 6.3 g of 1-bromo-2-fluoroethane and stirred for 2 hours. The resulting reaction liquid was filtered with cerite, and the filtrate was added under ice-cooling and under nitrogen stream to a tetrahydrofuran solution of disiamylborane prepared by using 75 ml of 1 M borane-tetrahydrofuran complex and 18.5 ml of 2-methyl-2-butene and the resulting mixture was stirred for 8 hours. Then 3 N aqueous sodium hydroxide solution and 30% aqueous hydrogen peroxide were successively added under ice-cooling to the reaction liquid obtained above, and the resulting mixture was stirred for 1 hour. The reaction liquid thus obtained was extracted two times with diethyl ether. The combined ether layer was washed with saturated aqueous sodium chloride solution, then dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue obtained was subjected to silica gel column chromatography to obtain 1.1 g of (RS)-3-(2-fluoroethyl)-3-cyclopenten-1-ol. Yield 16%

Source